If you want to do it right, buy lowering coils. They are made stiffer to compensate for the drop, and the ride will be better. Cutting a stock, old coil gives you a rough ride. Once you change the coils, cut the bump stop in half to give to more suspension travel. Now would also be a good time to change the lower control arm, sway bar, and strut rod bushings with urethane pieces, and check the idler arm for play.