Exhaust from a 323, 325, 328?

[Max55]

I was wonding if an exhaust from a higher model BMW would flow better and emit less noise . Wouldn't it be quieter than a 318is muffler and weigh about the same?

[Boyracer]

I was wonding if an exhaust from a higher model BMW would flow better and emit less noise . Wouldn't it be quieter than a 318is muffler and weigh about the same?

Definitely would flow better but not sure about the noise. If there is not enough flow compared to exhaust diameter it can has quite loud booming sound until flow increases, this is the case with my custom 2,5" exhaust. Between 2500 - 3100 revs you cannot hear you own thoughts but it is quiet below and above those revs.

Also, the exhaust are significantly heavier because of dual pipe construction and larger mufflers, increase is omething like 10-20 kg.