I just bought a 3" offroad ZZP stainless bolt on downpipe and I'm wondering if it is made to only bolt up with the stock exhaust manifolds or, can I use it with headers also. Thanks!

No. You do not use that downpipe with headers. Totally different configuration and design with headers.

No. You do not use that downpipe with headers. Totally different configuration and design with headers.

So,what downpipe works with headers? Also, what mods are a definite necessity with a 3.3" pulley?