I have been doing the same research. Here is a quick summary of what I have found.
Yukon install kit is probably the "best", part number YGA-14067 at Summit. But a lot of people have good results with something less expensive. You can piece mill a parts list for a lot less. Yukon and US Gear ring and pinion sets have good reviews. Richmond has mixed reviews, but I notice Richmond makes two grades of ring and pinions so that may have something to do with it. Look at part numbers carefully. There are others with good reviews too.
Truetrac and standard Eaton clutch posi get the best reviews for street use and appear to be most common, but the Yukon and even the Auburn have good reviews too.
Stock is 30 spline. The upgrade is 33 spline. I think 35 spline is mainly drag race application. If you are replacing everything, I don't think the cost to go 33 spline is much at all, so it may be cheap insurance at little to no cost. There are c-clip eliminator kits, but most recommend to stay away from those for the street.
In a rebuild, all top shelf parts, carrier, gears and axles could approach two thousand in parts then add labor or do it yourself. An aftermarket complete rear end starts around three thousand with powder coating. There are a LOT of options out there... like everything it will come down to what you want to spend and it seems there are pros and cons to most options. On the low end, replacing everything can probably be done around twelve to fourteen hundred, maybe less. On the high end a complete aftermarket rear end with all the bells and whistles and mack daddy brakes is around five grand. There are a lot of threads on this website (and others) about this subject.
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