By The BMW E46 3 Series is one of the most iconic cars of the early 2000s. Everyone has a parent or a friend or a cousin or a workmate with an E46, or has at least owned one at one point or another. The point is, they’re accessible, and there are dozens of trim and body style combinations available. Fortunately, all E46s share a few major things: they’re all front engine, rear wheel drive (save for the three X models), and well balanced. The big daddy of the E46, the M3 coupe, is becoming a collector car. If you don’t have one yet you should consider picking one up while they’re available. If you do have one or are planning to get one, you’re probably also working on your mod wish list. One of the easiest ways to make your E46 M3 more powerful, more fun, and more loud is an aftermarket exhaust. The “M” does stand for Motorsport, of course. Exhausts can take many forms, from simple bolt on replacement mufflers to high performance headers and cat backs. We’ve got some recommendations for each style!
Axle Back
To start, we recommend Dinan’s Free Flow axle back exhaust. Dinan has years of experience modifying BMW’s vehicles, and makes plenty of performance exhaust systems and tuning kits for E46s. This simple upgrade replaces the OEM muffler, giving you a much louder sound without adding too much rasp or abnormal pops and burbles. This exhaust mod won’t give you too much of a power gain, but Dinan advertises an extra 7 horsepower at your S54 engine’s staggering 8000 RPM redline.
Cat Back
For a wilder solution, try a cat-back exhaust system. The E46 M3 exhaust uses an interesting split-dual midpipe, with two pipes from the header back. Instead of a midpipe that collects into a box muffler behind the rear bumper, a lot of catbacks will split into a Y-pipe with individual rear mufflers instead. This increases both volume and exhaust flow since your piping isn’t hitting a right angle at the back of the car. The Borla S Type cat back is an interesting upgrade for a few reasons. It offers fewer bends and less restriction than the standard midpipe and muffler, meaning you get better flow and about 12 more horsepower as quoted by Borla. Even still, it’s not significantly louder than stock, even smoother in the middle of your RPM range.
One of the louder cat backs for the E46 M3, the aFe MACH Force-Xp exhaust gives you the loud metallic rasp that BMW straight sixes are known for. It uses a similar twin pipe system to the stock exhaust, but uses a crossover in the middle both for support and to even out the exhaust pulses. This system offers a 14 horsepower and 13 lb-ft gain over the stock exhaust.
If you’re looking for a different sound, Magnaflow’s Performance cat back exhaust system uses a traditional H-pipe routed into a merged muffler. This creates a deep, guttural exhaust note unlike the other exhaust systems on this list. It also offers a pretty significant torque gain– about 10 horsepower, and 15 lb-ft.
Headers
The most noticeable changes to exhaust sound and performance on an E46 come from new headers. If you are upgrading from stock, nearly anything will provide better sound and flow, as many aftermarket headers don’t have built in catalytic converters. Keep in mind, these systems are the most complicated exhaust upgrade for your M3 short of a turbocharger manifold, and may not be legal if you’re in a place like California that doesn’t allow fun.
Speaking of fun, aFe makes headers for the E46 M3. The aFe Twisted Steel header is loud. It’s not a particular kind of loud, and not necessarily deafening, but it’s loud. It’s stainless steel and 48-state legal since it includes catalytic converters so anyone else driving (or racing) behind you won’t have to suffer through the eye watering toxicity of a straight pipe.
Meanwhile, at the extreme end of the spectrum, the Supersprint race header is widely regarded as the best option for an E46 M3. Supersprints are a great way to really get some power out of your E46, and pave the way for future engine mods, a tune, or a supercharger. They’re catless stepped headers designed for efficient scavenging and smooth flow across your entire power band. This header can give your S54 nearly 30 extra horsepower, and combined with a good cat-back system they can make your car sound like its track-special DTM siblings.
There are so many modification options available for your M3. Think of the possibilities– an all-out track car, an ear-piercingly loud canyon carver, or Need for Speed M3 GTR replica are all within easy reach with a little bit of planning and research. For a new exhaust as well as tons of other parts for your BMW E46 M3, check out the Motoroso Marketplace!
