The question I have is what will your rear suspension setup be? Is it going to be adjustable for pinion angle, or fixed? If it's an adj. 4 link or ladder bar, then you'll be able to dial it in to tune it. If not then it needs to be pretty spot on to start with.
I had my pinion nose down a couple degrees too much, and it drove great around town, but vibrated pretty good at around 55-65 mph. A small adjustment on my ladder bars to bring the pinion up and it all went away.