I would keep the current spring pads and get a set of H&R springs and bilstien sport shocks. Make sure your car doesn't have the self levelling rear suspension. I don't think Eibach makes a set of springs for the 230E(or CE) otherwise that would have been ideal.
The Bilstien sprintline kit which comes complete with shocks lowers 45mm but then you'll get into camber issues, same goes for the SPAX spring sets which get really low.
Hope this helps.