33x10.5 is what i would get, you gain diff clearance.
The weight of the car should be fine with that wide of a tire.
Me and my bro took his Toyota snow wheelin, we were laying down the fresh tracks. He has a 32X10.5 on it now, as long as we didn't give it tons of gas and get the wheels spinning it would just stay right on top of the snow.
A toy weighs quite a bit more than a zuk or track, i think you would be alright with the 33.
Plus if end up not liking a 33, you could always sell them and go down to the 31.
Amilla