Honestly, if you're going to spend the kind of money needed to upgrade anything in your rear axle, I would HIGHLY recommend you install a selectable locker like an ARB or e-locker. Being that you're in Carson City, this is especially helpful to have when it snows and or the roads are icy as you can leave your rear end open and lock it as needed on the trail. Being that you're wanting to upgrade your gear ratio, I would put the TrueTrac in your front axle as you're going to have to pay for labor regardless and so long as they're opening things up, that would be the time to do it.
Regarding shops, there's a reason why I make the drive down to Hanford, CA and have Disciple Offroad do the work - they are that good. That said, the only other shop I might recommend is Driveline & Gear in Sparks.
