Exhaust manifolds come in various varities and will depend heavily on your future turbo upgrade plans. If you're not worried about factory manifold bolt on turbo options (like 19T, ATP turbos, Kunigawa, etc) then I would go with a DEI/SPA Cast Exhaust Manifold which is designed for use with T3 flange turbos. It's a cast manifold (non tubular) so it will not crack like many tubular designs do and also has an external wastegate flange. I'm more focus on bolt on turbo options at the moment (easier, less new parts) but if you're going all out then a DEI manifold is your best friend. T3 turbos are easy to come by and come in a variety of prices from down right cheap ($300) to very expensive ($1300+).