Originally Posted by jgil089

You have 2 options. GPM make the gears in metal, so you can buy the full set including the internals which is expensive, or just the ring gear which is also expensive for a single gear but less so. RCJaz have the GPM gears

Or grab metal parts bag from the DF02 and the gear cases. This gives you enough to build 2 diffs for the price of a single GPM set. You need to file the pinion down a bit. I'm pretty sure its bag a, part 9400152, but you better check.

As a bonus the bag includes other bits like a 19T steel pinion which is a good match for a 13.5T and a bunch of those annoying self tappers Tamiya insist on using (I love Tamiya but wish they'd use proper hex head screws and bearings instead of bushings). Oh and another Tamiya hex wrench, you can never have enough of those.

I find that the metal gears slow the car considerably on the stock motor (have a couple TT02B's for my 5yo and his friends) but the 13.5T brushless setup like you suggested is the perfect match for the chassis and you don't notice the car being slower with metal gears on this setup.