All the Beltronic models like the BelSti are 1000% undetected by any system all over the world..
http://www.beltronics.com/
Not only are they undetected, they also have the best reception all round the vehicle.
I wouldn't be without one in Sydney.
Bought my unit from here:
http://www.ebay.com.au/itm/Beltronics-B ... 20b8924528