Dear gentlemen,
thanks a lot for promt replies!
The info was pretty handy and I did find some additional info on the Web. Besides I ordered that WDS Cd on E-bay. You right, some features will not work on my '83 oldie without the interface, something like seat memo and so, but that is OK. The main idea is just to fire the unit up. Once it is fired I am sure that GPS will work by all means. The problem is that wiring harness lacks a couple of plugs, including, as I thing, the one that goes into power outlet. Actually it is not a big trouble - it only needs more time to make it work. Anyway, thanks a lot for your hints. Once I bring it to life I will inform you about the results. Thanks a lot.