Hi, what does the delete of cats on a N54 with replacment with the N55 mid pipes do for performance, i.e horse power and throttle response? Will it be picked up by BMW or can we still maintain our warranties? I also heard that this mod produces a bad smell, is this true. What does it do for the sound, I have the bmw perf exh. I really would like to do this conversion if it works and looks the same as oem.
Last edited by Imo135; 09-14-2011 at 11:01 AM.