For the sealant on the plugs and manifold studs, just use liquid teflon pipe dope.
Use a gasket on the thermostat housing, and lightly coat each side with permatex, just a thin light coat spread evenly with your fingers.
Also I used the TTI flange pipes on my manifolds, they fit great and hooked them up to summits 2.5 duel exhaust kit.
I only had to buy a small straight section and added a extra set of header flanges to hook everything up, it came out nice.
