i have a racingbeat catback installed with the stock cats, precats still on. now, im wondering if i put a racing beat streetable header with the stock main cat, will the stock main cat able to handle the change? thanks

 

It should be able to, but if it is old then it's a crap shoot. Also the RB header won't bolt straight up to the stock cat. You need a little like 3" adapter piece, or buy a Cork Sport header which will bolt up to the stock cat. If you want to run with cats I would suggest getting a high-flow cat from Bonez or something though.