Changing rear suspension height can affect front wheel alignment angles. It really depends on how much you change the height. This is also why you should have the vehicle loaded the way it is normally loaded when used. I had a customer that I did a few alignments for. The first time he came back about a month later with new tires scrubbed off. After talking to him a few minutes when he came back to complain. We found out that after the alingment he would load up is vehicle- 350lb wife (no joke), 3 teen agers in back seat, trunk jam packed fulland pulled a travel trailer to the mountains. When you load a vehicle like that you change the frt end geometry conciderably. Threw alignment adjustments out the window.