I know you've probably already made up your mind, but just some FYI: With the 15x7 and 3.75 backspace the rim/tire is just about against the control arm. Removing any material on the hub and/or wheel will cause problems. Going to a 17 opens up more possibilities due to the wheel being able to go further over the control arm. As you can see from the tirecalc site, Dodgestang's 245/40-17 is the same diameter as a 215/60-15, not counting minute variances with brand, tread type, etc.