alright i have abuilt b20/vtec and right now i have an amuse exhaust sytem witch is very rare and cost me a pretty penny but is only 2i n all the way thru and the headers i have has a 2.5 in flange so i was wondering if it worth it to go ahead and change the exhaust to a 2.5 or 3 in or just leave the 2in on there also will there be any power gians by changing the exhaust yes i am getting it retuned in about a week so i would like to get it done sooner than later if its worth changing and wat is the best brand to use for all motor setup......