Well I agree about the turbo refinements needed.
But about the trans., It's the same transmission used in Supras and holds up fine, also very common in Jeeps with the 4.0 that is often pumped up.
X2 with the turbo...and same with the transmission...just remember your gearing decisions in the front, rear, and T-case plus wheel size is the big factors...
I have a 22R with a Weber, Offy and header connected to a A340 and put in 4.88's and I should of went to 5.29's or even lower. The OD is way high and I can only use it on flat highway. But then again I didn't build this for highway driving, I just need to remember to take the backroads to the mtns.