ok first off i'd like this to say on topic, not looking to start a debate about the possible cons of cutting a coil spring. i've read up a lot on this and know the proper way to cut the spring without harming the temper of the steel. with that being said i've decided to switch from the bilstein pss's im running now to a set of koni sports. i already have a set of front eibach lowering springs i'll be using. though i need a similar drop in the rear. frankly im just not looking to spend anymore than i have to and being i have two sets of stock e39 m5 springs i figure why not just cut a set down a bit. so my question is how much should i cut off the spring to achieve a similar drop as the front? thanks.