Electronic Damping Control (EDCIII)

To All,

First of all let me tell you that this is the best web site if you have a BMW! I myself am the owner of a '91 BMW 750iL. Currently I have a problem with the EDC system installed in my car. My current control module (BMW part#: 37 15 1 138 760) is defect. I am looking to replace this part but the module is very expensive at the dealer ($300+). Is there any other way to get soft damping (i.e put 4.5V 2Amp direct to the dampners??)?

Would it be technically possible to use other EDC's with a different partnumber? Or do I need to use the ETK EDC module partnumber?

Thank you all in advance for your effort in awnsering my question...

IceTea.