Unlike the previous E92 M3’s high-revving V-8, the new S55 engine swells with torque and offers improved drivability. It may sound like an industrial air compressor at cold startup, but its full 406 lb-ft of twist hits at just 1850 rpm, with 425 horsepower peaking at 7300 versus the old V-8’s screaming 8300. Once warmed up, the aural signature goes sinister.