The guys at USA Bikes advised against it (was going to use a 4 Stroker); said the pedal clearance wasn't sufficient. With 2 stroke you have plenty of clearance.
The 3 piece cranksets that come with the 4 stroke kits do the job well; used it on my Felt MP.
Let me know how you like the GT2; the double wall wheels & Grubee HD Axle kit are worth the price of the whole bike, the frame is icing on the cake. The only negative is you ride high in the saddle ([I am 6'], which can be rectified by putting a smaller rim on the rear & a fat 3" tire (motorcycles have this setup).