[adc]

1. Extend the time with car to maximize your $400 investment.
2. If that is not possible, rent an M3 like someone else suggested. Except rent it from BMW Welt which has this cool rental program.
3. if not possible, just eat up the cost and don't think back.

I still think your time with the car is way too short, you need a few more days for a proper bonding.