Originally Posted by 90civic_Si

depending on if all the stuff that you are putting on is NAME BRAND LIKE AEM DC SPORTS GREDDY.. all that good stuff.. then prolly about a good 30 to 40 hp.... when i added my headers.. resinator w/2.25 piping. and n1 apexi muffler / AEM CAI i added about 45 hp..... but it all depends on the way and how you do it with what kinda sutff.. ya know/