GPS GSM Tracker in my Sprint FHC - Which one?

[bloodknock]

Hello People
In the final stages on my journey, before I finalise the dash and trim on my Sprint FHC, I thought I might fit a hidden tracker device. I dont want any on going contracts, just a PAYG sim for texts. I am very nervous of the quality of those offered on EBay out of the far east and so would seek the advice and experience of yourselves.
I'm particularly interested to hear from anyone with good long term usage experience, and of course, those to avoid!
Thanks
Bob

[billwill]

The far east one works and is far less expensive.

Giff-Gaff seems to have the most suitable SIM usage terms for use in this way.

Though even in sleep mode it runs down the battery if the car lies unused in a garage, but months not weeks.