Have a 94 GT and have replaced from the cats back with flowmasters and now have removed my whole exhaust to replace the clutch. While everything is out,should I replace the rest of the exhaust with one of the new x-pipes and if so what do you do as far as the o2 sensors and the air tube that hooked up to the cats on the stock system. Have been looking at the x-pipes in Jegs catalog/is this something that would improve performance or should I just stick with the stock cats and h-pipe?