Any wheels with more than 6" of backspace will not fit any lift that uses new longer spindles. The trucks with leveling kits have stock spindles. That is why the wheels fit. I'd start searching for different wheels if you are going to lift your truck.

 

Ok, so heres the deal. Since I can't run a 20" Rockstar with a 4" lift, what about running a 18" wheel.

This is what it says on the installation manual for superlift:
For 35x12.50 tire: 18x8” wheel with 5.75” backspacing, but the rockstar is 18x9 can that work??

I want to stick with a 4" lift kit, just dont want to go with the 6" lift.
I was reading the other forums and it says that they do manufacture a 18" Rockstar with 6x135s bolt pattern, and 5.5" of backspacing. Just want to know what all you think about this. sorry for the changing of kits and wheels.

 

The height of the lift does not determine the backspacing. It is the replacement spindles that determine the backspacing. Pretty much any wheel with 6x135 bolt pattern, and 5.5 will fit. Doesn't matter if it is 20" or 18".

 

Yes, that will work fine.