Should I go with an aluminum or steel spacer. I am getting a 2 inch spacer. Don't want to spend the money on a steel one, if an aluminum will do the job. I don't really tow with the truck much anymore, and will rarely have anything heavy in it. What do you guys think. Also, the ones on ebay range from 121 mm, 126 mm, to 130 mm. What are you guys running? how do i know what size I need without taking my wheels off.