I have set of rear springs for a E90/E91. These are same springs also found on the M3 KW kits.
KW Part number is 2017 (60210152) which denotes to be a 630lb/In spring. KW street comfort, V1 and V2 come with 2012 which is a 570Ib/In spring. So these are an upgrade for those wanting a firmer spring in the rear, they are a direct replacement, ideal for anyone who wishes to track there car or simply increase performance characteristics of there suspension.
Based in the UK but for the springs and shipping Via FedEx is $250.00
As you can see I got these directly from KW Germany. They are 100% genuine and brand new unused.
Any questions please let me know.
Thanks,
Am.