Twelve seconds, one camera position, a parked car. That is the entire video, and we are going to build an article on it anyway — because for once the clip is honest about what a dyno video never shows you: a real car, in a real workshop, with a real valved catback fitted, being revved by someone who does not care about your camera angles.
The car is a black BMW M2 G87. You can see the carbon ducktail, the lit OLED taillights, the M2 badge, and a rear diffuser carrying four black-tipped outlets — two low, two high. The plate was already blurred by the customer before we received the file, and we pixelated it again on our side, because that is the rule. A yellow banner reading "FOR BMW M2 G87 EXHAUST SYSTEM" is burned into the bottom of the frame — the customer's own edit, left as-is. What follows is everything those twelve seconds can honestly tell you.
What the S58 actually sounds like
The G87 M2 runs the S58: a 2,993 cc twin-turbo inline-six, 460 hp at 6,250 rpm, 550 Nm from 2,650 to 5,870 rpm, 9.3:1 compression, rear-wheel drive, six-speed manual or eight-speed automatic. It is the same engine family as the M3 and M4, packaged into a smaller car. The 2025 refresh took it to 480 hp, but the architecture is unchanged, and the architecture is what you hear.
Two turbos change the sound before the exhaust does anything. An inline-six has a perfectly harmonious firing order — three combustions per revolution, no gaps — which is why the architecture howls. But the turbos sit between the cylinders and the tailpipes, and they act as flow restrictors that smooth the pulses. The result: a strong, rich mid-range and a muted top end compared with a naturally aspirated six. That is the character you are hearing in this clip, and no exhaust can undo it. What a good exhaust can do is decide which part of that character gets emphasised.
We measured the audio. Overall mean is -11.7 dB with a -2.7 dB peak. The 100–800 Hz band — the straight-six's fundamental and first harmonics — sits at -14.0 dB mean and -1.6 dB peak, essentially the loudest part of the recording. Below 100 Hz drops to -15.9 dB mean. Above 2 kHz collapses to -36.8 dB mean, 22.8 dB below the mid band.
Three things drive that >2 kHz figure, and only one of them is the engine. The phone microphone rolls off hard above a few kilohertz. The turbos smooth the exhaust pulses before they reach the tailpipe. And the car never approaches its limiter in a stationary twelve-second pull — we never hear a full-range run, only part-throttle work. Treat the top-end number as a floor, not a ceiling. The mid band, by contrast, is real: at 3,000 rpm an inline-six fires 150 times a second, and that 150 Hz pulse and its harmonics are exactly what the 100–800 Hz band captures.
What the clip actually shows
The car sits still in what looks like a workshop or storage unit. Someone revs it. The camera does not move. There is a silver coupe in the background and a red lift stand, and for a moment a person crosses behind the car. That is the whole frame, and we are not going to pretend otherwise.
What matters is the hardware. The rear diffuser carries four black-tipped outlets, which is the layout of our M2 G87 SUS304 valved catback, Center 4-Exit. The ducktail spoiler is carbon. The taillights are the thin OLED units. Nothing in the frame is staged; this is a working car in a working space, which is the only kind of customer footage we trust.
The honest limits: one microphone, one position, one afternoon, indoors. A workshop is a reflective box — concrete floor, metal walls — and it flatters any exhaust by adding reverb the open road would not give you. We do not know the exact throttle position in every moment, and while a stationary rev in a workshop is almost certainly valves-open, we cannot prove it from the audio alone.
Why stainless is the default answer for this engine
Our material rule has not changed: engine character decides the material, not the price list. A 9,000 rpm naturally aspirated flat-six pushes us toward titanium, because the thin, stiff wall preserves the high-frequency attack that makes those engines shriek — the 718 GT4 RS is the strongest titanium case we build, and that argument is made in detail in its own sound article.
The S58 is the opposite brief. It is turbocharged, it makes its torque from 2,650 rpm, and its exhaust pulses arrive at the tailpipes already smoothed by two turbines. Titanium's main acoustic advantage — keeping high frequencies alive — has less to work with here, because there are fewer high frequencies to keep. What the S58 does have is a thick, vocal mid-range, and that is exactly the band where a stainless wall adds weight. The 540i article makes the same argument from the other side of the range: a BMW straight-six whose character lives in the mid-range, not the top end.
Weight is a smaller deal than the internet thinks. A valved catback is roughly 12–18 kg in stainless. Titanium saves perhaps 4–6 kg. On a 1,700 kg car that is a fraction of a percent, felt by nobody on a public road. If someone tells you titanium makes an M2 faster, they are selling you something.
Durability is a bigger deal. If the car sees winter, rain, or a damp garage, SUS304 is the material that still looks right in three years. Titanium develops heat tint — some owners love the blue-and-gold gradient, others want the system to look the same on day one thousand as it did on day one. Both positions are legitimate; they are just different positions.
Two ways to build an M2 G87 exhaust
Route one: stainless valved catback, Center 4-Exit. That is the system in the clip. Four outlets, valves retained, factory-style operation. It is the choice if the M2 is a road car that should sound mean at part throttle without turning every commute into an argument. Our M2 G87 Center 4-Exit catback is the published version of exactly this build.
Route two: titanium valved catback. Lighter, brighter, and it takes the heat tint beautifully. We build the M2 G87 titanium valved catback for owners who want the look and the note rather than the weight saving. If you are deciding between materials on a smaller engine, the 330i titanium article and the 330i stainless article show what each material does to a four-cylinder, and the G70 article makes the twin-turbo stainless argument on a V6.
The full BMW range is in the For BMW collection, alongside the wider catback and titanium alloy lines.
The honest warnings
Twelve seconds is not a review. There is no drive-by, no on-boost pull from low rpm, no A/B against the stock system, and no titanium M2 in the same place on the same day. What we have is a stationary rev in a reflective room. It tells you the car sounds mean; it cannot tell you how the system behaves at 5,000 rpm on a B-road.
A four-exit diffuser is a commitment. The Center 4-Exit layout needs a diffuser with the matching cut-outs. If your car has the standard twin-tip diffuser, fitting this system means changing the diffuser too. Check what your car has before you order.
Valve control has to be right. The G87 has a factory valve system. An aftermarket catback that ignores it leaves you with valves stuck open — loud everywhere, including at 6 a.m. — or stuck closed, which wastes the system entirely. Ask for the integration details before you buy, not after.
Indoor clips lie upward. Concrete and metal add reverb and bass build-up that the road does not. If you have heard this clip and thought "that sounds huge", it will sound slightly smaller outside. That is not the exhaust; that is the room.
A question for the owners
M2 G87 owners with a valved system: how often do you actually drive with the valves closed? The stock system's quiet mode exists for cold starts and early departures, but the S58 is a turbo engine that does its best work on boost, and on boost you want the valves open. Does the stainless four-exit give you enough theatre in the daily mode, or do you find yourself reaching for the button every time you start the car? We would like to hear what you chose and why.
Questions we get asked about the M2 G87 exhaust
Stainless or titanium for an M2 G87? Stainless for road use, durability, and mid-range weight; titanium for the look, the heat tint, and a slightly brighter note. The engine is turbocharged, so the acoustic difference between materials is smaller than on a naturally aspirated car. Choose on looks and budget, not on promised horsepower.
Will the four-exit catback fit a standard diffuser? No. The Center 4-Exit layout requires the matching diffuser cut-outs. Confirm your car's rear diffuser before ordering — the bolt pattern is not universal.
Does it work with the factory exhaust button? It should, when the valve controller is integrated correctly. We recommend keeping factory-style operation so the quiet mode stays intact.
How much louder is it than stock? On this clip the system runs at a -11.7 dB mean against a -2.7 dB peak, with the mid band dominant — a substantial step up from the stock system's muffled character, especially at part throttle. Exact figures depend on the car, the tips, and the diffuser, and we would rather give you the measurement than a marketing adjective.
HMD builds the BMW M2 G87 exhaust range in SUS304 and titanium, valved and straight-through. Browse the catback and titanium alloy collections, or message us with your model year and diffuser type.