Also not true. Once you get to a certain point it is the rear that cannot keep up with the front. Due to our rear coil over being so short we hit a point where the insert can't be any shorter because most coil over company's don't produce a cartridge that small. However the fronts have a lot of room to be shortened.All coils can go low in the rear. It's the fronts that need springs/valving if you want to go slammed and be even with the rear.