i have a clifford matrix rsx 3. 5, supposed to be top of the line, but basically the same as viper. it is one of the best things i have done to my truck, the remote start is very nice to have, it is set to run for 12 minutes, the turbo timer is set for three minutes, and it is nice to not have to shut down the truck at every stop. it is also very nice to just hit the turbo timer button, arm the system and walk away. i bought mine off of ebay for $230(do alot of research, and get a new in box unit not remanufactured junk. ) and had a buddy who works at a car stereo store install it for $100. very well worth it in my opinion.