I installed Phoenix Secure GPS Tracker in my Sx4 car on 22 March 2013 & I just got one more installed on 24 March 2014 in my brand new Duster. The company technicians were proffessional enough while installing in my car. The services are also very good including the SMS alerts on Door open & car ignition.
I even get a voice call at night in case of door open or ignition on. Very good security device, must install in your car. Many more Reputed companies also available but Phoenix was recommended by my friend. The device is costly but I got a very good deal from car showroom.