Is there anything you can do to compensate for the offspacing? I really dont understand the concept to begin with...

 

Minor note: They are 2000 and under ZQ8 wheels. In 2001 and onwards, the ZQ8 looked like:


And as for backspacing...that's the difference between the mounting surface of the wheel at the lugs, to the back plane of the rim. Basically, if you decrease the backspacing/offset, you push the wheel farther away from the center of the vehicle, and this makes the wheel more likely to rub in a turn (makes the radius of the wheel's turn longer).