I use the HPI beval gears. Be sure to do the 4-Spider mod though, that will save you fron buying more gears to replaced stripped ones. This mod will prevent them from stirpping so easily.
I'm getting the HPI 4 spider diff gears and was told that they might be better than what is out there. The cross pins are one piece compare to the others that are out there, and told that a less chance of the gears floating in the diff case with the HPI set.http://www.hpiracing.com/buyhpi.htm, then to Savage 25 option parts, part #87193