Whilst I am sure not as good as Ryders, have been using this for a year now
http://www.amazon.co.uk/Tracker-Vehicle-Theft-Protection-System-Black/dp/B003XDN58K/ref=sr_1_2?ie=UTF8&qid=1417180006&sr=8-2&keywords=tracker
Dead easy to install (2 wires). Metal casing. Cheap to run
Location...