Re: diff gears
I had 3.23. 2750rpm @100.
Acceleration was better then 2.77, and it did LSD burnouts. Much more responsive at any speed.
Fuel economy was worse on freeway, but about the same, if not better around the streets.
3.45 will be better for acceleration, but will obviously rev higher.
If you have a 4 speed, go for the 3.45, and if you have a 3 speed, it's up to you, but the high revs might get annoying.
CAUTION: Slippery When BOOSTING!