Required to align the rear end when using a QuickLift Rancho Front Coil/Stand. This makes the truck level; However, my 2007 Tahoe has a front rake and a tapered rear roof. After the car is leveled, it looks like the cargo area is heavily loaded and the roof is sloping backwards. Alignment also lost 3mpg and I will be replacing the rear spacers with larger ones to restore the car's aerodynamics. Also, I have 305/45/22 tires and there is still a lot of friction around corners.