On a side note the kyosho gear diff works as well they just don't stock it at my lhs.

And yes temp can affect the diff but you can compensate by running thicker or thinner fluids.

And anyone who doesn't think that gear diffs can't be every bit as good as ball diffs they should look at Team Durango as there 4wd buggy, SCT and there upcoming 2wd buggy are all using gear diffs, and lets not forget everything 1/8th scale does as well.

For me this just works better but your mileage may vary.