I've heard good things about the HKS GT2540 Turbos. I hear that they make pretty good power and they bolt right up to the stock SR manifold. If you have a KA you plan on building, or have built up, get a custom manifold done or you can get a GReddy KA Turbo kit or the XS Engineering T3/T4 Kit. Either way, I think you will have a pretty good power band. I think the GT2540 hits about 320 at max boost, and if so (because I can't remember) I know the GT2850 hits 300 easy and the GT3037 is about 400. Either way have fun, and good luck.
Mini me