why all that work?

1987 300TD and a 1995 E320. It would be nice to have one key for both cars.

if the key blank is the SAME FOR BOTH cars then you can flip the key.

what i mean is take the first car...1987 300TD and have a key cut for it on only one side, then take the second key pattern, the 1995 E320 and have it cut for that on the other side, there is only one set of tumblers in the locks and the key can be cut on two sides for two cars, just file a notch for a car to fit..

eg - notch the E320 side

common thing to do with a replacement lock or ignition and dont want two keys...

that is IF BOTH THE KEY BLANKS ARE THE SAME...i am not sure that they are..

Hope this helps, or is helpfull for the future
Jake