Replacing upper and lower arms

What is your question?

I'm planning on replacing upper and lower trailing arms (back), on 2002 Nissan Pathfinder 4x4. Here is the dillema. The only space I can use is a driveway , that slopes side to side. In other words, if I'm standing behind the car, I can see it tilts. Passenger side sits lower. The few forums I checked, day that car has to be lowered to original height, before final tightening of bolts. After I have replaced the 4 arms. If my driveway is tilted would it affect that final step? Meaning, proper leveling?