While searching for ways to hide the tank and engine I came across this thread. On GPS you can get a boost phone rather cheap, service is only 10 every 3 months. I did this a year ago using info from InstaMapper - Free Real-Time GPS Tracking
. My plan was to catch the thieves that stole my sons bikes 2 times already. Not sure how to hide the phone and keep it charged though. Maybe someone here has an idea there.