Ask a sounddesigner about that...
You adapt the engine's sound by changing intake and exhaust parts! The 360 Modena as much as the M3 have a rather tinny sound coming from the std. exhaust but both on their respective sportier versions (Stradale and CSL) sound so much different and better (in my eyes)!
Of course the basic layout of an engine is the most important part of it, but don't underestimate the influence of the above mentioned.