I have the Toad 606 on both my 1.4 & gti and its a great little unit, got boththem off ebay abotu £100 each, from Precision Alarms i think, based in Canvey Island, Essex. Got good service from them, easy enough to install, had the guidence of a ex-alarm fitter, but its pretty much plug & play. just make sure you have your haynes about

Keep a eye on the sensertivity, can be a bit over sensertive when windy so makesure you install the brain with the screw for adjusting the sensertivity faceing out, found cable tieing it to the heater air supply thingy was the best bet.
Good luck
