all you need is the main cat, you dont need the other cat after the exhaust manifold
i have a random tech that was put on with my apexi, but to tell you the truth you're better off keeping your stock cat and putting the $225-250 into some other performance mod. i went to the exhaust shop and the guy told me there is no such thing as a hi flo cat. im not sure if that was the truth, but i didn't notice any major difference in performance at all.
maybe that would be different if i had an rb25.
