Update today:
I now have 1 working XMod after swapping the Fets around.
Fiddled about with both boards, and after taking some Fets off and trying them on the other board, I now have a fully working car
However I'm now in need of either another pair of battery holders, since one set keep getting wayy tooo hot... Or I'll just convert one car to Lipo, thus eliminating the need for the holders as I can just cabletie the LiPos on.