What's the problem with....
 

Whats the problem with running stock wheels on a procomp lift? i thought i read somewhere on here it isn't recommended. Why not, can someone explain?

You need the right size wheel (width and backspacing) to clear the suspension component's in the front. Check with procomp on wheel requirement's.

I believe it's because of the design of Pro Comp's knuckles.

Yeah your OEM wheels wont stick out enough to clear the design of the lift. Go with a Rancho lift if you want to use your OEM wheels. Their 4" lift will actually give you just over 5"

Nearly all 6 inch kits are this way. Many also widen the track width 1.5 inches per side. It's done for clearance issues. The back spacing has to do with the rim clearing the tie rod when the wheel is fully turned.

You can also run stock wheels and deep backspaced aftermarket wheels with the Superlift kit.......which is one of the main reasons I went with that one.