The aftermarket exhausts out there do not fix one of the design flaws in the stock exhaust. If you look under, the driver side pipe comes out from the cat and just joins the passenger side in a 'T' type fitting. Not too favorable. What should have been done is a collector type fitting that resembles a 'Y'. Not only does the 'T' cause turbulence, but will cause unnecessary backpressure going back into the driver side downpipe. I wonder if everyone with cracked headers had the first cracks showing on the driver side. This would definitely cause heat build up in the driver side header due to the inefficiency created by that junction. I am going to replace everything from the cat (right after) including that junction and dyno the system. I am probably going with a Flowmaster dual in/ dual out and running dual exhaust 2.25" OR doing a Y collector running 2.5" ( because I'm supercharged) all the way back in a single exhaust. We'll hopefully soon be getting to the development work on this project.