I've been really busy lately with work/travelling, so I apologize that I haven't been able to dig up the name of the German company that sold me the unit.
However, I did a quick search on eBay and this is the same unit:
http://stores.ebay.com/USKEYLESS
It is exactly the same unit, but I recall paying about $50 US for the whole thing.
If anyone wants to look up the actual company and has some time, here is what I recall:
-I bought it from ebay.de not ebay.com
-There were two guys running the company, one was named Pepaj
-The name of the company was "Funk-Fernbedienung" or something close (this means Keyless Entry in german). Their ebay id was something like "funkferbedienung" or maybe it had a hyphen between the two words.
Shouldn't be hard to find.. if someone finds it, post it here and I'll verify it's the same place.
As I mentioned, I think I paid $50US. Can't remember if that included shipping or not, but I recall shipping wasn't that expensive (maybe $20 at most?).
Took me 40 mins to install as I didn't hook up the "flash parking lights" feature. That would have required a wire from the headlight switch to the trunk which would have taken longer to do than the entire installation! I just lock the car and listen for the click of the doors and/or hear the vacuum pump run.
BEST upgrade ever! I sold my W126 but would have put one of these in right away!
Figure $20-25 a piece for the blades, and you have cool switchblade type remotes WITH keyless entry for about $100!
Difficulty level: If you can install a car radio, you can do this.
Install note: They make you cut a green wire then connect two wires from the unit to these two new green wire "ends". It DOES matter which wire goes to which end, and there is no way to know in advance. Make SURE you attach the wires temporarily and try it out before permanently attaching wires! It won't hurt anything if you have it backwards.. the only thing that happens is the unit doesn't work. So it's pretty easy - hook up the two wires, test system, swap the wires if necessary, and you're done!
Neal