I need a shop that works on rear diffs

[gr8scott72]

I want to get the rear diff out of my 93 and have different ring and pinion put in it so it's like 4.3:1 instead of the stock 3.9:1 and then put it in my 94. Can someone tell me where I can find the gears and what shop I could send the diff to to get the work done?

Thanks