I don't know if it's been pointed out on this thread but there is a good reason that ball diffs work better. A ball diff's action doesn't change with load. Aside from the balls loading against the holes in the diff gear everything is just as free when under load as when it's sitting idle.

A gear diff under load is trying to disassemble itself (all the gears are driving away from each other), add to this the lower quality of RTR level parts and that silicone oil is only ok as a lubricant and what you have is bind. Better quality gear diffs work better but these are rare in 1/10. The Kyosho is the best I've seen and the only one made well enough for competition use imo.

Ball diffs can be difficult if not adjusted properly but once guys get the hang of them they last a long time between re-lube/rebuild. The 22 doesn't come with carbide diff balls (a crime for a competition level kit imo) and has apparently had some trouble with the lock nut but fix those two things and you should be sippin' drinks in happy town.