400hp
Listen; **** the jspec motor and the 6cly.
Go to a professional machinist and have a long talk with him. Internals are the best place to start, it not all about how much psi you have, it's about the internals. He will tell you "any good machinist anyway" that light wait rods, good pistons, sleeves, port and polish head, and so on will get you the most power. Turbo and supercharging is just the kick the motor needs for its full potential. Now go and find the best machinist you have in your area.
Good luck.