Originally Posted by
3DRCRACER
Gear diff vs ball diff is a personal preference so I won't comment on that. I have however purchased two of the serpent gear diffs and they are a direct swap other than shimming. Very nice pieces also. Be aware there are two gear diffs offered by serpent, one has an aluminum exterior gear and the other one is plastic. Other than that they are the same. I run the aluminum version in mod and the plastic in stock.
I definitely recommend gear diff for carpet. Don't bother with the Losi RTR diff, just get the Serpent one. I run the SRX-4 diff, which has the aluminum outer gear. It is usually $5 cheaper than the plastic-gear SRX-2 diff, but I think that's just a supply-demand thing. They are otherwise identical, and you can interchange the plastic and aluminum outer gear on either.