I'm running 15" Enkei wheels and I noticed that my front tires are flush with the panels (properly spaced in my mind), while the rears sit in the wheelwells a couple of inches. Are there any problems associated with shimming the rear wheels only? I'd like to move them out an inch and a half or so to fill the wells.

 

No problems as many people have done this before.

 

Remember, when you shim out the rear wheels, your car will understeer even more. You really see a huge improvement in your handling if you pair up the rear spacers with with a stiff rear sway bar like progressive.

 

That's exactly what I had in mind. I'm going for the "look", but I want it to perform as well.