Hiya, I got a 3.5 sports and am wondering if a 3" exhaust is to big? Of course i got all the hopes and dreams of modding more in the future, like everybody else, but is it to big? Are there any gains to be had from it? Or is it just noise? The reason is that I've got a cat back 2.5" exhaust and am wanted to replace the rest of the exhaust from the flex pipe to a high flow cat. So im wondering if just replacing the whole thing with 3" piping is worth it.

u wont lose anything by doing it as proved by RPW on a mildly modified car

but if ur wanted to do bigger, better mods (cams and stuff) 3" would be the way to go

Save your money. I've run 3" for my supercharger system later this year. The 2.5" system will give you good torque returns across the rev range, no advantage going to 3" unless you expect a 20%+ increase in exhuast gas volume from your motor.

Re-doing the header union will help free up some more torque and match the cat diameter up with the rest of the system. Don't do the dump pipe until you've installed a GOOD set of extractors, some systems come with new flex pipe and plumbing to the cat.

Oh yeah I forgot to mention that I've got Pacemaker Extractors already, 2.5" for unmodified and 3" for future modifications basically