Turbo blocks are the same as non turbo, except for the addition of oil squirters under the pistons to help cool things down. I'd say you'd be fine either way. All differences between electronics are in the head (CAS) and throttle body (TPS, ETc.), really. A 6 bolt or seven bolt is how many bolts on the flywheel. 6 bolt is generally accepted as the better of the two because the 7 bolt motors are prone to "crankwalk" which is (simplified) basically when your crank gets a lot of play in it, and can destroy the motor quickly. You can use a 1g 6bolt on a 2g head, but you'll need all the 2g electronics to swap over unless you have a standalone. Really, it seems as though you'll be fine with any 4g63 bottom end, it just depends what your goals are. Performance/Longevity= 6-bolt turbo block Simplified fix/ Replacement= 2nd Gen. 7 bolt. Ironically, the 7 bolt motors are sometimes more expensive. I have a couple of each if you are interested, but they are of course bare blocks, which are all in fantastic condition. Lemme know. hope that helps.