[jtrolinger]

no no..a cat back system exhaust connects to the back of ur Catalyc converter..u have decided to buy 4-2-1 headers witt a high flow cat so ur original cat. is gonna have to b thrown out..the headers connects to the high flow cat (which is really a test pipe by the way) and ur exhaust system whether or not it's brand new connects to the high flow cat.. I would say buy the cat back exhaust system because whats the point of the headers and high flow cat if ur getting restricted by the stock exhaust system..I have the same set up in my 99 si..except I have 4-1 (1 piece) header witt a high flow cat (test pipe) just like urs and a cat back exhaust..good power gains but= HIGHLY ILLEGAL!!!..haha