Definitely get the D16A6!!! It can produce good power either all motor or turbocharged. You can get a z6 head, some zc pistons and rods, zex cam, and fuel management and you will have a nice all motor setup with 12:1 compression. Or, if boost is more to your liking you can build a kit with an HF manifold, a T25, a Mitsubishi Starion front mount intercooler, and engine management running around 6 psi. I have seen this setup put down 175 hp and 168 ft lbs. which would make your car very quick. Either one of these budget setups will yield nice numbers and pretty good times at the track.