[stephenp]

no put them in before the cat and run a toggle to turn on a o2 simulator and back pressure loss only contributes to lose of a slight amount of torque unless you are idleing at like 400 rpms and have no manifolds \or headers and you might (very slight chance) singe an exhaust valve its a myth that you burn something up ive got a 92 saturn that i run 421 headers o it and thats it and she runs like a champ andf thats all allumkinum and its pretty neat to see a saturn that spits flames and sounds bad ass (well actually it is bad ass nort only sounds it tunintg by me)