Simply because its has LONGER gears and you'll be IN boost longer doesn't mean it is better for FI. Bottom line when your drag racing (if thats the intended use of this build) shorter gears will prove more potent. Somewhere between an LS tranny and ITR tranny hence: GSR tranny would always be my pick...but its up to you. You don't want your gears to be too short when you may have traction issues. You'll spin off the line and b4 you know it you'll have to shift into second and so on and so forth...

I say stay with your initial choice...

[EDIT] ^ true point about auto trannys with FI, hence when driving a turbo 5-speed, you have to get better at driving the car and you're shifts will become quicker and quicker and hence less loss of spool. One must learn the car they drive first.[EDIT]