Hereís a pit I fell into, maybe it will save you some grief.
I did some research and decided on Yukon Gears. I purchased the master rebuild kits as well as the gear sets when i caught a good sale and the $150 or so rebate running simultaneously.
I canít (wonít) try to do this job myself itís above my pay grade, so I set out to find someone I could trust to do the install.
Little known to me but most shops donít want too, or wonít install gears that they didnít supply. The reason most quote (and it makes perfect sense too me), is that if a warranty issue arises, so does an argument between the gear manufacture and the shop that did the work. His fault vs their fault yada yada.
Any way, it took some doing but I found a shop that does sell Yukon gears, and weíre willing to do my install but the price I ended up paying for the labor ate up all my savings from the sale and rebate.
If you canít, or donít want to set up and install your own gears, my advice is to find a shop that sells the gears you want. Let them sell you the gears AND do the install.
The route I took didnít cost me anything extra but it sure was a PITA, and I had to drive a couple of hours to the shop.
This may not pertain to your situation but if it does, TIFWIW