You have a stage 3 Z with all cats in place which is identical to my brothers Z so I know exactly what you are talking about when you say you want more. You really haven't even scratched the surface as far as mods go though. The difference between his stock turbo Z and my stock turbo Z is night and day. With the right mods the stock turbos spool very quickly and provide plenty of power. Do all the breather mods,dual intake and 3" dp/tp and I guarantee you will be satisfied. For a little while anyways, then you can step up to bigger turbos.