1. just stick a few dabs of hot glue on the bead of the rim and slip the ABS/ PVC on. to get it off, just push... hard. it's better than the tire falling off during a drift (although that IS kinda cool looking... the first 3 to 10 times).

2. the other option is to make a tighter fit by wrapping electrical tape around the rim.

3. you'll find out how easy it is to change a wheel when you get a car. i can only describe it in less than one word.