Great decision I think Chris ~ tbh I'd have thought your exhaust was all sorted prior to getting the supercharger kit but at least it will be now.
The manifolds are probably the most restrictive part of our exhaust systems but also the biggest PITA to change. I was going to sort mine eventually but was thinking it would be much easier to do during a clutch change, ...if & when it needs one.
Like the Mishimoto rad cap too, I bought the small black one they sell to replace my fake Nismo one. Didn't fancy risking the cooling system for the sake of a fake rad cap.