Ecotec v.s. Subaru v.s. everything else

[lazylongboarder]

I'm in the process of building THE bug...his name is Gary (and no i'm not gay). I sandblasted the pan, welded new floor pans, installed an adjustable puma beam, lowered ball joints, dropped spindles, and i'm waiting for my brakes to come back from VwCustoms...14" rotors with red 6 piston mono-block calipers at all four corners (who needs an e-brake?) off of the front of the 2005 Porsche Cayenne Turbo. I'm going to be installing a 6 speed g-50 off of a 993.
Alright, porsche motors are a little rich for my blood and so i'm looking at some water cooled options.
I'm thinking the options are between the subaru and the ecotec motors. I'm looking for the most possible hp for the buck and i'm looking to spend $4000 to $5000 on the motor, computer, radiator, everything. I'm looking for a turbo motor to sqeeze the extra ponies out. I heard the ecotec motor can get a good 500 hp reliably but with internals. But who builds them?
According to outback motors, to get 350 hp and up out of a subaru motor you need a closed deck block, pistons, rods, you name it, including race gas and they only build subaru motors.
All options are welcome here.