Windowlicker, Id advise going the coilover route as well - dont be so tight with your baby
I put mine on about a month ago and Im absolutely loving them. Initially I wanted exactly what you want - a nice drop to lose arch gap, without compromising handling. After a lot of research, I soon learned that I wasnt going to achieve this from just a spring. Your right in saying the springs are different on a CSL vs M3, they're differently rated - and this'll be why folk end up sitting higher. Im unaware of any companies that do a CSL specific spring too.
On my first drive with coils installed, I couldnt believe how it felt. There's NO roll and the steering is so direct. Its a little harsh of ride, so Im going to soften it up when I can be bothered!
Im running KW V3s btw, with a fast road geometry setup. Lowest setting in rear, and low enough in front!
Before for comparison
