[hotrodmach1]

the x pipe or h pipe is the middle section of your exhaust. you can use one or the other. the exhaust starts at the exhaust manifolds, which are bolted to the heads on your engine, then your h or x pipe. you have an h pipe with cats from the factory. the flanges are bolted together with a gasket between them. then you have your cat back which basically your muffler, tailpipe and exhaust tips. after market exhaust will flow more freely and will sound better. get under your car and youll see.