http://www.amazon.co.uk/Tracker-Vehicle-Theft-Protection-System/dp/B009ZCEBOK/ref=sr_1_5?ie=UTF8&qid=1410928854&sr=8-5&keywords=car+tracker
without giving away too much the additional shock sensor is around £3.50, piezo sirens a couple of quid
my unit lives inside a welded box installed when the vehicle was completely stripped to a chassis, would need a major strip and work to find / remove
power is by an auxilary fire alarm sealed battery so cut the main battery leads all you like still runs for upward of 30 days... piezo sirens are securely mounted in two inaccesible locations so even if one was ripped out there is an equally hard one to get to still going off
if the vehicle battery gets low I get a text immediately
if it gets knocked or someone trys a handle or breaks a window the sirens sound for ten seconds and i instantly get a text telling me position and sensor alert
if needed it can be geo fenced and will also send an alert if speeding
in the event i get an alarm text I can diasble all vehicle electrics leaving it dead in the water
in the unlikely event it was stolen i could do a hard stop by instantly cutting all electrics (illegal if moving but who gives a toss) or a soft stop where all cuts when vehicle stops
it will turn on a microphone concealed in the cab
can monitor fuel to alert of syphoning and various other tweaks
runs off a sim card that can either be a top up when empty or I have a £5 a month package for unlimited as I like to text her regularly to check on battery, systems location status etc (sad I know)
only one of several layers and certainly isnt there to replace the disklock, pedal lock, cut outs, alarm and additional security deadlocks on all doors but you can never have too much security... after all the idea is only to make the next one down the road an easier option... no security is perfect but you need to do what you can....
Cheers Steve