Originally Posted by RaihaX
is 2.25" for 135i if that helps
disclaimer** I am not 100% on that
2.25" no shit? that's tiny! going to a 2.75 or even 3" full catback would show absolutely immense gains, 2.25" would be choking the shit out of the engine in even stock form - even evo's and sti's love a 3"
ima need a second opinion on this one, cos even bmw surely can't be that silly!