man if i were u, i would save up and get a nice suspension lift if you havn't already done that.
But do u what u want. A body lift would only void if something got messed up cause of the lift. For example, they could blame your Air condition from failing cause of the body lift. If u have drive shaft problems then u would have to pay for it. Also, i am under warranty to and i want a suspension lift, Go in and talk to the manager and your dealership about your waranty to see wats up. GOOD LUCK!!