Stay in the 300 series of turbos, no need for 400 series. As Matt said earlier, the 64.5 is a great turbo and spools pretty quick. A 66mm or somewhere around there should do you just fine. I know transmissions were also mentioned, that will also help with spool time if you're an automatic, mainly the higher stall torque converters. With 205/100s or even a smaller nozzle size such as an 85 will do you just fine. If you aren't interested in towing much at all a 225(or larger since you're going with a thumper pump) injector size will be fun, but at the expense of EGTs. But that again can be fixed with a turbo! Haha. Again let me know, if I can get you anything for this build! Matt can hook you up with some of their non-vgt setups!