On new Nissans and Mercs as well I think, they have alarm/central locking systems that lock/unlock as you aproach or leave the car respectivly. You don't have to push any buttons on the key fob, its just done on proximity.

Does anybody know if you can buy aftermarket kits that would fit the coupe that do this. Anybody have one fitted?
Cheers

Its activated by a credit card sized fob.

Yes - you have a key or a alarm fob, but you don't have to push a button to unlock the car, you can just leave it in your pocket aproach the car, and it unlocks...

It uses transponder technology, this way it knows that you are in fact the owner. Or at least you have the right key/fob/transponder.

So as you approach the vehicle the transponder transmits it's code the car reads and verifies the code. When happy it is correct the doors unlock, when you leave the vehicle and the current transponder is no longer within a given proximity the car locks again.

There have been after market systems like this, but i'm not sure if these are still in circulation or even still produced ! If there are still available you would need to make sure there would be no conflicts between this and the O.E. immobiliser !