For sale are lightly used (less than 3k mi) springs from a Ground Control coilover kit installed on my E30. I've gone with slightly stiffer spring rates.
Specs:
2 x Eibach 2.5" ID ERS Spring-- 6" 400 lbs/inch (0600.250.0400)
2 x Eibach 2.25" ID ERS Spring-- 5" 500 lbs/inch (0500.225.0500)