Can anyone answer me about which Cat does what and which one can i remove and still be legal. Ive got a WRX 97 which has two Cats fitted, ive had conflicting info. over which one i can remove to have the best power gain versus legality? Some have said the first cat at the down pipe is just a pre-cat, with some saying its the second one? Please can someone advise?

 

I think WRX's only have one CAT and thats in the down pipe..!!!! the box after the down pipe is just a resonator..!

Dan