gear diff is worth the money?
R-spec gear diff ever leak?
Depending if you're using it for front or rear... my TB03 is for drifting, I use one way front and gear diff rear. With the rear, I use 550 wt damper oil to keep it smooth, seems to be working and no leaks.
So far the gears inside haven't stripped on me yet. I stripped one from 3Racing on my mini. Overall they are definately easier to maintain, never have to rebuild them so far.