hey guys.. i have remove all cat on my car, and i now use my oem muffler to keep enough backpressure.. i'm not doing any dyno yet. but i already do some dragrace with my friends 255hp manual toyota altis. his car 0.5s faster than my 325i.
my 325i is 2.5l euro spec-> k&n cone filter+bms powerbox+ Stock 17 inch rims with rft tyre
my friends toyota altis 1.8 turbocharged with lightweight rims + semi slick tyre
now i am still looking for some aftermarket exhaust, because my car sounds very weird..