1+
The only real reason for an extra set of rims is so you can ruin good tires(a tire in good health) at the track and then remove them for your lame el cheapo street tires. Plus you don't really run around with them OEM rims I had one spin out in a hairpin turn and the tire unseated its self from the bead of the rim and well that rim was destroyed pretty epic. $900 bucks for those OEM wheels...

 

This x 1000. If there is one thing I wish I did was track the car mostly stock, so I could feel the effect every mod made.