I recently installed my Summit O/R H pipe, and it sound pretty decent when under 3000 RPM, but at WOT it makes a very loud popping noise. Is this just the nature of the beast with my Borla cat-back or could it be a rich condition? Also, I just found that 2 of my header bolts had backed out completely on the #4 cylinder. I am going to replace the missing bolts and see if it helps. It just doesnt have the mean Mustang note that I love, its more like an old Chevy truck with exhaust..