Well, I have just fitted the Sakura diff gear in my TC6, no dremel here only a couple of parts changed.
You need a set of outdrive from a RRR V1 kyosho ref No: VZ219 (can be found cheap now)
I changed the internal gears for NT1 metal ones, the originals were plastic, but I guess they will do too.
The bearings are the same size, there is plenty shims to adjust your diff.
And you need a 40t diff which comes extra. (37 and 38 gears are standard in diff, 39 and 40 are separate spares)
It could be interesting to try a 39t on front...
On the minus point, you cannot use blades anymore, except if you remove some of the outdrive, which I did not want to.
So instead, I fitted some heatshrink on the ball and pin ends, it fits nicely with smooth action.
I am at the track tomorow to test all this if weather permits.