Yea, the ball diffs can give some feeling of resistance. But you also have to custom shim them in too. The manual is not always right as they can differ between every model. The part where it has the shims as 2x 10x0.3 on the long side and the 10x0.3 on the soft side that go on where the 1510 bearings go could be just a bit too tight.
I bought Tamiya 53588 shim set. It comes with 10x 0.1, 10 x 0.2 and 10x 0.3mm shims. So ten of each (30 all up). Makes for good fine custom adjustments.
Works across many models too.
(Included motor), Yea, I think they do that for many models. Outside of Japan they always include it. I forget exactly why, but I think it's to make the kits more "value added" for their foreign markets.
(Last edited by mv75 : 7.20.12 at 5:39 am)