I have a 03 X5 3.0i AWD and I have been told that I can't do staggered due to it not already have the computer setup for staggered wheels. It came with the same sizes all the way around (17's). Now I want to go to 20's and stagger them but I was told that I may have computer issues with the traction control due to the tires not being the same size. Please clarify?????