who is running 17 up front and 18 in the back? did you have to do anything to the car?

 

No reason it would not work, just why would you? If you had the width/profile in a certain configuration, the tires could even be the same diameter. More often I will see smaller rims in rear so a higher profile drag slick can be installed for launching.

Jazzer

 

i like the looks of a larger rim in the back. it makes the car seem like the rear is high and the front is lower.