Does anyone know of any good reputable shops in the Pittsburgh or Erie area that you would trust to do this job and be able to tell what shims I would need for the install? I am getting an '07 Z and with the new redline and engine it gets up to 160 in the top of 5th...seems like a lot of unusable speed and would be a perfect application for the 3.9 Final Drives. I don't really care if my top speed is lower...I'm never going to go that fast.