central locking kit

[car.crash]

has anyone fitted a remote central locking kit to their 5. i dont like putting the keys in my door and scratching the car.
im looking to fit somthing like this, are they difficult to install?

http://cgi.ebay.co.uk/Keyless-Entry-System-Remote-Central-Locking-Upgrade-Kit_W0QQitemZ150321499394QQcmdZViewItemQQptZUK_Car sParts_Vehicles_CarParts_SM?hash=item150321499394&_trksid=p3286.c0.m14&_trkparms=66%3A2%7C65%3A15%7C39%3A1%7C240%3A1318

[djinuk]

i put a similar kit on a fiesta, the basic jist was, ,, power earth to the big box, and then you have to signal wires, one went on 1 wire to the central locking motor the other one went to the other.. if you have them the wrong way around then it locked, when you pressed the unlock button, so pretty obvious :P