Yokomo GT4 or NTC3?
Wow! Well it depends on what model NTC3 it is. If it is the RTR version, then go with the GT4! The GT4 will have a bigger engine on it, two speed tranny, faster, and better handling. The GT4 is a much better car in my views. You can go to yokomo's site and see a video of the GT4 if you wish. The thing is real fast.
I have seen both the NTC3 RTR and the GT4, and I was much more impressed with the GT4. And about the parking lot with belts and rocks and shaft driven stuff like that: I will tell you that there are problems with shaft driven vehicles, but you will never have to worry about rocks. It is un-likely that much will happen to your belts and gears, but it could happen, and if it does, then no biggie. Just get a new gear or belt, for whatever happened.
So over-all, go with the Yokomo GT4! Have fun.
Hope this helped,
Kevin