SACHS list 6 front springs for the W211 they are all basically the same size but vary slightly according to coil OD and wire cross section altering their spring rate slightly. They have a 1blue 2 white coded one but be slightly wary of EPC who tend to stock one size [rating] fits all. If they can guarantee SACHS and the correct colour code then fine but they have been known to supply a "SACH's equivalent" citing stock availability in the past. You are safest with MB and bearing in mind you have to dismantle the front strut to install them that's the route I would chose- and you will do both sides obviously.