I just got a 6" pro comp lift installed and took my 2" leveling kit off i heard you can put a leveling kit on with lift kit to get more lift how true is that and if you can does it affect the ride any and can you get truck aligned properly

 

I would not stack a leveling kit on top of the 6 inch spacer with the standard Pro COmp lift. If you have the Stage II lift, you don't need to add a leveling kit because you can crank up the preload on the adjustable coilovers for more height.
But yes, people have stacked leveling kits on top of their lift kit for more height.