STS with or without cat's and headers?
 

Ok does STS work better with headers or manifolds and with or without the cat's? What sounds nice as well? I've been debating the pulse & velocity affect with and without cats and am unsure of the best combo.

I have Mac off road pipes on my (delete cats). When I first put them on, it did feel like it made a difference, but I haven't had a chance to re-dyno to see the actual #'s. I'll tell you it got a lot louder without the cats.

No cats worked better for me too. I'm with stock headers.

Cast manifolds and MAC ORY would be a good combo. Getting rid of the cats would definitely help increase power :)

Stock headers for me. A week after my STS install, my cats came apart on their own and temporarily clogged the turbo. Getting rid of them upped it another 15RWHP, anyway.

So for an STS setup with ORY how much worse are the 98-99 type headers than the 01-02 manifolds? I'm not liking the idea of converter guts tearing up the turbine wheel.

When I gutted my cats the turbo spooled quicker and seemed to have more power. I had long tubes when I put the turbo on.