I source my trackers from USA at a good price. I use long life battery operated units for ease of removeability, but I get hardwired versions for my clients from time to time. They're both very good, customer service is terrific, and I would recommend them. Tracking is charged on a month by month basis, which means there is no long term contract to sign up to. That's one of the main reasons why I went with these guys. Use this website:
http://www.spyassociates.com/index.php?osCsid=f8fe6de61b129f123d46f012609c47eaThe trackers I use are called Spyhawk GPS. It's my weapon of choice and I'm a P.I. If you want to send an email regarding further info to suit your needs then use this:
SpyAssociates@aol.comAddress it to Jeffrey Jurist and if you want to just mention me, Dennis from Eyecon Investigations, in Australia. He'll look after you.