Exhaust Buying Guide

Due to the number of customers we see who have had a stainless steel exhaust fitted to their car by other companies only to find the system is totally unsuitable we have decided to put together this report. As market leaders, we feel customers should have a better understanding of the pros and cons of exhaust systems in order to make an informed decision.


In this report we would like to help you to understand what to look for when you’re on the market for a new stainless steel exhaust system, the reason we have decided to do this is purely for the fact that we receive so many enquiries from customers who have had exhausts built by other companies and have had major issues, and to be honest some of the work we see is way beyond a joke, some people have literally wasted their money and have had to cut their losses and get the whole job done again, properly, needless to say that not all companies are producing poor quality work and supplying inferior products however to reduce your chances of being duped into believing what they say, we strongly recommend you read reviews, talk to customers who have had work done, go on forums and make sure you are able to see examples and look deeper into the reviews as some companies create their own but most importantly ask to see the mufflers they are fitting along with tubing and make sure you fully understand the sizes and diameters they tell you what will be installed in your vehicle and after the job has been completed ask to view the job and check the underside and make sure it does match what you were told as in most cases we see companies talk to you about having a certain diameter pipe fitted but install something a lot thinner and cheaper.

There are many factors that will determine a good stainless steel exhaust system one of the most crucial components is the actual silencer or as Americans call it the muffler. Anyone can make a claim however the important factor is to see evidence to back up the claim, one of the biggest complaints we receive from customers who have had exhausts built by other companies is that the exhaust is far too loud but when they drove it away from having the exhaust fitted it sounded reasonably good but over time it has become louder to a stage where driving the vehicle has become extremely difficult due to the constant loud drone which is like a booming sound emitting from the exhaust.

Most companies never show you the underside of your vehicle, they don’t even show you the mufflers and the workmanship all you get to see is a pair of shiny tailpipes, here at Profusion Customs we are proud to document our work, by photographing before and after pictures, and making sure our customers are educated on what work we propose to do so the customers have better understanding of how the final result will be.

We believe in clarity and giving you the right information to enable you to make the right informed decision. Below you will see an illustration of a typical Profusion Customs muffler identifying areas which sets us apart from other mufflers available in the industry, when customers are shown a muffler which may be fitted to their vehicle all they see is a shiny tin can however what you see on the outside is of little importance compared to the inside of the muffler and how it is built. We will identify each area of the muffler and explain its pros and cons.

When it comes to choosing the right exhaust system for your car, the first question customers ask is:

How much will it cost?

It seems customers have a fear that they may need to re-mortgage their house to get one, yes at one time stainless steel exhaust systems were only affordable by the rich or dedicated enthusiasts, however in recent years we have seen prices have come down to a degree that now anybody can afford a stainless steel exhaust system and in some cases it can work out cheaper than the one supplied by dealers.

Engines work very differently, technology has progressed from early vehicles, so a muffler used on a new BMW may not be suitable for an old classic vehicle therefore it is important to establish if the company you are dealing with has the right products at hand for your specific vehicle, there are many companies that boast they have a wide selection of mufflers and carry huge stock, ask to see the stock and the variety of mufflers the chances are there will be unable to show you as they only order them in when the need arises.

We don’t profess to be the only company capable of doing a high quality job, now will we mention which company is the biggest culprit, it seems they are doing a good job of damaging their reputation anyway, I’m sure there are good companies are out there however this report highlights the issues we hear from customers and hope this can help you to find the right partnership, equipped with the right knowledge.

There are many factors that determine the outcome of a good exhaust system, such as:

  • Muffler/silencer
  • Core diameter
  • Tube diameter
  • Wall thickness
  • Bend options
  • Engine capacity
  • Performance
  • Fuel economy
  • Sound
  • Hangers
  • Manifold/headers
  • Catalytic converters
  • Resonators
  • Tailpipes

And so on, I think you get the point, in this exercise we will talk about one of the most important parts and that is the exhaust muffler/silencer:

Unlike standard exhaust mufflers which rely on baffles and Chambers to keep the sound down, majority of performance exhausts do not have any baffles or Chambers to restrict the flow, instead they have a straight through perforated tube which is surrounded by sound deadening material.

Unfortunately there isn’t a one muffler fits all option and yet there are many companies providing just that solution by fitting a muffler which is suitable for 1.2 corsa’s into high-powered vehicles or petrol mufflers in diesel vehicles. The majority of complaints we receive from customers who have opted for a budget system are that the exhaust sound has become much louder after a few months of driving or they have noticed an increase in fuel consumption with loss of power, or cracking and leaking joints, when we ask why they decided on that exhaust system the answer is always, because it was cheap. I think that says it all, people are duped into believing that a budget system will work exactly as a top end product. The sad thing is, in their endeavour to save money they end up spending more money in the long term to fix the problem apart from all the aggravation involved, we hope to give you enough information so that you don’t fall victim, saying this we have also noticed that some companies have raised prices but still supplying inferior products to make you think that you have paid for a top end system, that’s like paying for butter, thinking you are getting butter, but you get margarine

There are a number of brands of stainless steel exhaust providers in the UK and without naming anyone: we will highlight what to look for, we do urge you to read reviews and conduct some research before you decide on an exhaust system.

We will highlight and conduct a comparison of a typical exhaust muffler compared with a top end branded MagnaFlow or Profusion muffler.

Ribbed Body, some companies use really thin wall steel and the only way to strengthen it is to create some ridges. These are normally unbranded, thin wall can also create resonance which can add to a tinny sound. Welding hangers to the body is not advised as it creates a weak point. The body wall may have a folded edge at the joint.
End Caps
These can be either flat folded at the joint where it meets the body, resulting in possibilities of leakage due to the constant expansion and contraction by heat or a thin weld is applied to both edges, resulting in a join that could split open, welds can be ground down for finish. The continuing pipe is welded straight to the end Causing an extremely weak point.
Internal Core
The perforated core may be made from other materials as 409 stainless steel or even mild steel, this is just a straight pipe cut at angle to go from one side to the other, very poor construction. To keep costs down a narrower core pipe may be used causing restrictions.
Internal filling
the cavity is usually filled with a glass fibre mat this is a very economical way to fill the muffler however this is also prone to vibration and the shockwaves can break down this material and can eventually pass through the perforated core so over time there is possibilities of ending up with an empty tin can with no silencing properties.
Fully polished muffler
some mufflers are polished to a mirror finish this includes all the welds, overall you get a muffler that looks fantastic however it may not perform as well as it looks because as soon as the welds are ground down and polished all the strength of the weld has been removed and these are prone to crack, there are many examples of this on the Internet and many are sold online and look beautiful however we remove many of these and they are nothing more than an empty tin can. Some companies in their endeavour to make as much money as possible will simply import cheap mufflers like these from China put their stamp on it and people are duped to believe they have a high quality product from a well-known supplier.
This type of design is usually made in-house and not in a factory environment, it is simply a rolled flat sheet of metal, not the best for strength, these can cause resonance and produce a booming or drone sound.
End Caps
These are usually cut from flat sheet and pressed edges which are simply heated together to fuse the end caps to the body, this can create weak points and the seams are prone to splitting.
Internal Core
Mostly made from low grade stainless or mild steel but is only inserted to the length of the muffler and does not extend to give a stronger form. The tube is then welded to the end cap and not the tube, creating weak points.
Internal filling
Glass fibre mat is a very economical way to fill the muffler however this is also prone to vibration and the shockwaves can break down this material and can eventually pass through the perforated core, manually filled so consistency can be varied, so over time there is possibilities of ending up with an empty tin can with no silencing properties producing a loud drone.
Fully polished muffler
This type of muffler is only polished to eliminate scratches, there is no branding and is only as good as the person putting it together, no real technology is used and can be produced cheaply by almost anyone, mostly used by people who just want a cheap system.
Fully Polished heavy-gauge 304 Stainless Steel, which requires no additional strengthening. Fully branded. Heavy wall reduces the chance of vibration and resonance therefore creating a much deeper sound. The body of these mufflers can be welded anywhere. The joints are fully welded for additional strength.
End Caps
Heavy-gauge press curved end caps which overlap the body which is fully welded creating an extremely strong product, hangers can be welded to any point. Wells are only polished, not ground down. The continuing pipe is never welded directly to the end Back to the protruding central core pipe for a strong join.
Internal Core
Fabricated in 304 stainless steel and is mandrel bent to follow the contour to allow ease of flow, the core pipe extends the full length of the muffler and protrudes approximately 3 inches either end to allow the exhaust tubing gain a solid join.
Internal filling
The internal core is wrapped with fine stainless steel wire hundreds of times which prevents the acoustic fibre from vacating out of the muffler this means that over time there is no degradation of sound and creates a much more of a deep tone rather than a tinny sound. This process is very expensive to adopt however all of our mufflers use this design.
Fully polished muffler
MagnaFlow and Profusion mufflers are fully polished however the welds remain intact and are never ground down this creates a much stronger muffler which is built to last, this is by far the most superior silencers on the market.

Exhaust fitting companies

How to choose the right company to install your exhaust system, in the UK there are many franchise companies and dedicated independent workshops, some are specialists whereas some are general servicing garages.

We have seen many workshops open up offering lifetime warranty exhaust however within two years they have packed their bags and gone leaving your lifetime warranty worthless, we have also seen general service garages who are struggling to make money because of their poor workmanship and start building exhausts thinking it’s easy and work behind a facade of fantastic marketing, to get customers but only offer budget mufflers which may not be suitable for every vehicle.

Some boast that they only use TIG welding but they don’t tell you that TIG welding is only good if it is purged, which welds the inside at the same time and leaves a smooth finish, otherwise you are left with just one side welded and produces a small weld area, as exhausts expand and contract MIG welding can be a better option but it depends where the weld is applied, we use TIG and MIG but will decide the areas which will benefit from MIG or TIG.

At Profusion Customs only specialise in stainless steel exhausts this is why customers have driven to us from Europe as well as almost every part of the UK. We take a very open view, we provide clear instructions of what we propose to install we make sure you have access to the best mufflers and components and we make sure you are satisfied with the end result.

There are also many other factors that will determine the best company or products to use however we would end up writing a book so in this report we hope it will help you to make the right decision when it comes to building a new exhaust system on your car.


IMG_9763-2Customer bought this muffler from ebay because it was cheap and looked shinny, paid a company to install it to his BMW, within 8 months the packaging had blown out and all he got was a very loud boy racer sound, loud Drone, came to us to get the right mufflers fitted according to his car.

Buy cheap you buy twice, the whole experience was costly and frustrating, if only he came to us first.

IMG_9767Customer thought he got a great deal when he was quoted £600 to build a cat back exhaust on his Mercedes by a well known budget exhaust company, not only had they used the wrong mufflers, but the welding was done in mild steel, where one of the hangers broke and had to be towed home at considerable expense.

Buy cheap you buy twice, the whole experience was costly and frustrating, if only he came to us first.

IMG_9769Customer went to a budget company and paid for a 3 inch stainless steel exhaust for his Subaru, he couldn’t understand why his fuel consumption was so high and the car felt underpowered, he went to the company but his claim was rejected, came to us and when we removed the muffler, we realised what they had done, his 3 inch system had 1 3/4 core in the muffler which caused the problem, this is a common procedure used by many exhaust companies, hence why it was so cheap.

Buy cheap you buy twice, the whole experience was costly and frustrating, if only he came to us first.

IMG_9778Customer opted for a cheap exhaust thinking all stainless steel exhausts are the same, the ends broke off because the tube was welded to the end and not the core, he went back but the company had changed business name but same people working there, another common issue for lifetime warranties.

Buy cheap you buy twice, the whole experience was costly and frustrating, if only he came to us first.