The Passport SRX and the K40 Calibre are both systems that have sensors at the front and rear of the car with the control unit inside. There may be others, but those are the 2 that I remember off hand. I had the Passport in another car and it worked quite well. As for mounting the S1/V1 combo, I have my S1 in the are by the homelink buttons/overhead compartment, etc. with the V1 mounted to the windshield in the space between the visor and overhead.