Get a lot of head work done. Think of the engine as an air pump, the better the air flow passes through it the more power you'll make. Wait a sec, the engine "is" an air pump! Just send out your head to a good machine shop where they have a flow bench and expect to drop about a grand or two to get the most out of it. That's what I would do.

When is the money spending going to stop on this fucking car?!