so i just put in a 2.5" mac off road h and i have felt a loss in backpressure. is there a way to get it back, lets say if i get 2.5 catback. i have the 40 series flows welded in to my stock cat back.
saying it fixes the sound sounds bad. lets just say it rounds the sound out. like adding dolby stereo. after this get a C&L plenum and accufab 75mm TB. i'm assuming you already have a K&N filter.. wait out on a MAF, you can have your stock maf recalibrated when you get your tune at the end. this is of course if you're staying N/A.