I'm planning to install a keyless entry system on my W123 300D this summer. This should not be too difficult of a project. My thoughts are:

1.) Since pretty much all keyless entry systems activate the locks electrically, I need something that will (by remote control) physically move the driver door lock knob upward.

2.) Relays to flash the headlights upon lock/unlock won't be too hard to install and I can do it easily.

When the project is finished, I'll be sure to post pictures and detailed instructions. Tell me your thoughts/opinions, and thanks for your support!