It was a hard decision

[Patrick]

Will an 18t pinion be a bit overgeared? It should be ok for speed runs, but if your going to use 10000mah, that's along time to be running.
The MM and/or 8xl might get a bit hot after running that long on a high gearing.
I could be wrong and it might work ok, but if it was me I would try it on a smaller pinion first (maybe 15 or 16) to see how that goes and then gear up later if temps seem ok.