Want to eventually install a 4" lift, however with the truck being new, no need to replace tires right now and cost for the lift, I was thinking of having Bilstiens installed on the front, 1-1.5" spacer on the rear. Question is if I do so will I need to replace the rear shocks when installing the rear spacer? second question, if later I add a 4" lift will i be able to keep the Bilsteins on the front? Third anyone have any clue what i should be looking at for an install price or install time??