I've always avoided exhausts as something for the chavs and it looks like the standard pipe works on the 318i is fat enough. any point in putting a freer flowing backbox on for performance? Performance is my only interest. Simple rule:
if it's loud but makes me go faster. I'll have it.
if it's loud and makes no difference, or slows me down. it's chav (just like the k&n I took off)
what are the relative differences, befefits etc between changing backbox, manifold and full system? and how good is the standard system?












