You will have to put spacers of the same size on all four wheels if you really want to. I've thought about this mod before but apparently it's not practical for the XI model. For example, if you want to add a 10mm spacer to the rear, you'll have to put the same 10mm spacer on the front too. But by doing that, the front wheels on our XI model will be sticking out of the fender.

 

Hey Bambi - why is that you have to do the fronts too? Does it throw off the AWD system? When I called H&R, they said I could do the rears and not the fronts. they offer it with audi all the time. what makes our cars different than audi's set up?

 

You have enough room to play with a 5mm spacer but thats pretty much it. Although I dont think its worth the money and possible vibration for 5mm of spacing if you dont truly need it.