Hmmm, must have been a different one on ebay, the pic looked like it was only a 4 pin square plug. It's gone now so doesn't really matter, but I'll check for the plug in the car some time. As for the original problem with this thread, check all your air intake connections, I remember on my first VL that the clamp to the throttle body weas left u undone once and whilst driving the car started to splutter then died and wouldn't restart. Found the loose clamp, did it up and the car fired straight away and never missed a beat ofter.

Ah, sorry Waughy. Should have clarified. There is the large 16 (or so) pin plug under the dash pad that the anti-theft unit plugs into, and a four pin plug that the key plugs into. So, provided the loom in your car could accomodate the system, you would have bought the key to plug into the four pin plug. Then you'd still need the anti-theft unit. Also, that plug next to the throttle body is probably the TPS (throttle position sensor). They're not connected in manuals. Disconnecting it in an auto will make it run like my incarcerated business associate's retarded gay neice. Some original photos have not been recovered yet.

My bet is the security key. I've had trouble with it in both my Calais. If you aren't using the factory alarm/immobiliser you can just bypass is by joining the 2 pink wires together. The switch stuffs up and cuts power to the ECU.