This car 2 yrs ago ran the same setup I'm putting back into it with no problems... Pacesetter header system, 2 1/2" Test Pipe, and 2 1/2" piping all the way out the exhaust. Had no problems... the problems I found were that I had 2 exhaust leaks (BIG ones) so I went ahead and ordered a testpipe from SBR and called Pacesetter for the other parts needed to solve my problem. The car hasn't run a catalytic converter in 2 yrs. The whole catalytic converter... back pressure changed my mind after reading this... why would I want to restrict when it ran this same setup 2 yrs ago with no problems? Black Venom and Jordan made me realize the mechanic guy who told me the whole back pressure thing and needing a cat was full of crap. It was his welding skills that messed everything up causing the system to have 2 exhaust leaks. Which is why I believe its running like crap. As soon as I get the parts I will be posting how everything went. BTW, before Saturday it was running stock NT headers, 2 1/2" Test Pipe, with 2 1/2" Piping all the way to the exhaust with no problems... the reason the original pacesetter header system was taken off was because the downpipe split in half. But when the system was on the car it ran perfectly fine.