nope it has no affect whatsoever. 17,18,20,22,26...whatever. doesnt make a difference. if you change the overall diameter of your wheel/tire combo you'll have to adjust the speedometer with a tuner

 

Another thing to consider is the smallest rim you can go with is 17". You'd have to grind down the calipers to fit a 16.

 

thanks again guys, i hate to keep beatinig a dead horse but im just about to order it all and want to make sure will have no rubbing. im gettin xd addicts 18x9 4.5bs with a -12 offset. for times im gettin 325/60/18 procomp xtreme all terrains (33.4x12.8x18r). once again i have no leveling kit. thanks a ton guys ill post pics when i order and get on!

 

should be good to go. thats gonna look SWEET! love the addicts

 

Backspacing is the result of a specified offset. Manufactures go based upon offset, but offset is difficult to measure. To get the offset you measure the backspacing. If you go to the link I gave and check out the chart. You will see that all 9" wheels with a -12mm offset will result in having a 4.5"backspacing. Hopefully that makes sense.