Looking good!

Cool you confirmed the TP specs are off on the weight. I'm really curious about your kv, did you check it yet with the Torque Control motor test in the Castle Link software? Don't know if the Traxxas firmware has that option, but you could use one of your MMPs or just flash your MME if it doesn't have it - it's a very useful feature in the genuine Castle firmware anyway.

Great you can fit the 8 mm pinions. You could check aliexpress for some cheaper ones, if you want some more gearing options and not pay $20 per pinion. I don't have my computer with me, but I could check the gearing a bit later. I think xmod was running ~105 kph gearing without fan on ballooning tires.

I started out with a plastic spur too, but did strip it after a couple of times, and that was with the Leopard 4082 even. Hard to tell if it was a rock, stupid gear mesh, or whether Power was a factor. I think for off-road use steel makes more sense, because of all the debris flying through the gears. On-road you might get away with plastic longer, I mean XO-1 has plastic spur, so should be able to hold a bit of Power.

Cheers!