Finally, Installed my Omega REC-11+ unit and a siren.

BTW, the 95 C280 OEM locking system is actually a 3-wire system. Both front doors use the same 3 wires and the signal is not on a single wire.
There is a Lock, Unlock and Ground wire that controls the locks. This actually makes the install easier.

The overall install was relatively easy. The hardest and time consuming part was finding the C280 connection wires. Installed the unit under the dash.

But here's the 95 C280 connections found on my car (as yours may be different):

----Kit Wire--------------------C280 Location-------------
1. 12 VOLT Constant.............Red Wire – Power Block (under gas pedal)
2. Chassis Ground.................Brown Ground – Left Floor Wire Panel
3. Ignition...........................Violet/Blue - Steering column (used diode)
4. Trunk Release .................NOT USED (requires a trunk release popper)
5. Starter Interrupt .............NOT USED (OEM Alarm Starter Kill relay installed)
6. Headlights.......................Gray/Red (+), Headlamp switch (used relay & diode)
7. Parking Lights..................Gray (+) & Gray/White (+), Headlamp switch (used 2 diodes)
8. Dome Light Output............Front Door Pin Switch - Brown/Gray (-), Left Floor Wire Panel (used diode)
....................................... Rear Door Pin Switch - Brown/Gray/Yellow (-), Left Floor Wire Panel (used diode)
9. Power Lock Pulse..............Black (-), Left Floor Wire Panel
10. Power Unlock Pulse #1.....Blue wire(-), Left Floor Wire Panel
11. Siren............................Cut the Piezo wire (+) to Siren (+) wire (using relay)
12. Signal Antenna Wire........Installed under the Weatherstrip of the Front Drivers Pillar, held in-place with RTV

Hopefully, this will help someone else doing this!
Everything works: Headlamp/Parking Lights flash, Lock/Unlock, Panic, Dome lights & Siren churp.
Now that Ive found the Door Pin Switch wires, Im thinking of installing another set of relays/diodes to "Keep the Radio ON until Door Opens" mod.

KEYLESS ENTRY IS GREAT ! ! !