Best size exhaust for 325i?

[M20power93]

I wanna do a custom cat back exhaust with a magnaflow muffler and was wondering what size sounds the best, 2.25" or 2.5"?

[M20power93]

bump

[CabrioPunk]

What engine.... stock? Some say stock is best. Add a muffler/resonator for sound. Few folks seem to use eBay magnaflow...

[MR 325]

Either single 2.25" or 2.5" would be just fine.