Hey, ive been searchin around but i cant seem to find the answers to a couple of my questions. First off, I am looking at getting a Greddy 4-2-1 SS Header. Now I have searched and read up on them, but i cant find anywhere if you need to buy a new cat in order to instal the header. (Sorry if this is a big time noob question) Due to the header's pipping being bigger than the stock cat? As for my second question. I can't decide between getting a Apexi WS catback or a Greddy Evo2. I know the WS is chambered and the Evo2 is not. What are the effects of the chambered muffler. (Besides it being more quiet, i already know that) Like what are the effects performance wise? (I searched for this too, typing in chambered exhaust and just chambered and i did use archived search, couldnt find anything)
Thanks in advance,
Mike

 

You do not need an aftermarket catalytic converter to run the Greddy header. It will bolt up to the stock unit.

As far as your decision between the two cat backs, you're goint to find very similar results between the two of them. I would personally pick the Greddy because I love the way the their Evo exhaust's sound... not overly loud, but not silent.