My rears are X2's, by the way. So far we have these confirmed, I'll try to update this as more people post.
Confirmed E9x M3 Spring Codes
USA 2008 E90 6-speed, ZPP and ZCW: X1 Front, X2 Rear
UK 2011 E92 ZCP, DCT, nav: X7 Front, X4 Rear
USA 2011 E92 ZCP 6-speed, tech: X3 Front, X5 rear
USA 2011 1-series M Coupe: Y8 Front, Y8 Rear
Last edited by Richbot; 06-14-2012 at 08:52 AM.