Without getting into which car is stronger, look at your parts availability. 4wd cars are gonna break. What will be easier for you to get parts for? I have a Lazer ZX5 and I love it. If my LHS does not have the parts I need, I can order from A-Main and they can be here in 2 days. I have never driven a XXX4 but I know from fellow racers that it's rough track handling leaves something to be desired. The ZX5, on the other hand, has an excellent suspension design.