Do I need to unbolt the catalytic converter to install this?

No. This is a catback system, so you bolt it directly behind the existing cat. The factory cat stays in place.

Will this bolt up to my stock exhaust manifold and cat?

Yes, this system connects at the catback junction point. Test-fit before finalizing any connections to confirm alignment with your existing hardware.

Does this come with gaskets and clamps?

Confirm gasket and clamp inclusion before checkout. If needed separately, have those on hand during install to avoid delays.