I went to 3 different Firestone stores and ask to speak to their best alignment tech ,, found one that would do custom alignment he aligns drift cars,, and now mine too. went for the lifetime for 169.00, have used it 10 to 12 times so far,, every time i make a change, and that could be once a month. i take it for alignment ,, I have set the distance from front to back to be both the same after centering all 4 wheels,, here is a pic of my rear setup ,,well Rudy"s setup anyway. jim