there have been many tests that have proven that today's High flow cats can deliver just as much power as a test pipe and still keep you CARB or EPA complaint. (As long as you buy a Catalytic converter that maintains those standards of course.) So yeah just do yourself a favor and save your self the trouble of a potential $1k fine from a Dick cop for not having a CAT, and get a high flow cat. Oh and here is an article to back up these statements....

http://www.importtuner.com/tech/impp...ers/index.html