seanybaby, the kits you posted are FD specific, not for the first gen. You have to be careful with the kits, because of the way an external wastegate is placed on the platform, although the exhaust manifold of a 13b is the same dimensions, a FD kit puts the wastegate right into the fender of a FC. Both of these kits are capable of 400+ hp, not too sure that the OP is looking to go that high.

There really is not a company that mass produces these. But there are a few shops that have made them before.