My Interstate was burglarized less than sixteen hours after I brought it home for the first time. That's what I get for buying around the Christmas holiday and living in the big city.
I had already intended to install an alarm system; the thief just beat me to it. So, while the Interstate was in the shop installing a new Kenwood unit in the dashboard to replace the one that was stolen, I had a Viper alarm system installed. Not from any particular preference, merely that the company that installed the Kenwood unit for the Airstream dealer just happened to be an authorized Viper installer. It was just more conveninet to have the work all done at once.
The Viper system is modular; add the sensors you want. I got the tilt sensor, glass break sensor, motion sensor, backup battery module, backup siren module with its own battery. I did not get the proximity sensor, the remote start system, or the door sensor. Total price of the system, installed, was about the same as one annual insurance premium on the Interstate, or 1% of my actual purchase price.
I detest those proximity alarms that tell you "Please step away from the vehicle." I've set off too many of them myself, when a car with one parked alongside my car, and I was just going to my own car. Since I live in an apartment complex and there will be people parked alongside of my Interstate both at work and at home, the proximity sensor would always be giving off false alarms.
The door sensor wasn't actually available for 2011-and-later Sprinters at the time I bought the system, so I didn't have a choice. But when it came available later, I still didn't get it. Even if I was to accidentally leave the Interstate unlocked when I parked it, the motion sensor would still go off when a door is opened, even without the door sensors. I know because I tried it to make sure.
And I have no use for a remote start system. Having never had a vehicle with remote start, and not being paranoid enough to think anyone would wire a bomb to the ignition switch, it seemed like overkill. It also doesn't get cold enough here on the Gulf coast that I'd have to worry about getting frostbite while waiting for the interior to warm up after starting it, either.
I've only had a couple of false alarms during thunderstorms, and those were on occasions where lightning struck so close that everybody's alarms went off.
There is one drawback to the system. It will suck down the chassis battery in about two weeks if you don't start the engine from time to time to recharge. One reason why I drive my Interstate to work about once a week when I don't have any camping trips planned. If your Interstate has the auxiliary chassis battery under the hood (mine doesn't) make sure the alarm system is wired into that auxiliary battery, not the main battery in the driver's ide footwell.
Next time the local AAA office does VIN etching, I plan to take my Interstate in to get all of the the glass etched with the VIN. This will give me a slight break on my insurance premium.
Engineering: Finding complex solutions to simple problems you didn't even know you had.