Is it possible to put two different alarm systems on one car?

yeah it can work. It happens a lot when the factory alarm is heavily integrated with HU's etc. The real question is why do you think it adds extra security? It's just as easy to pop your hood and unhook your battery or cut your batt - to chassis wire and then smash the window.

not if he has a motion sensor or proximety sensor on it, the one i have on mine goes off if someone bumps it hard enough. its bolted to the body of the car from the inside so it don't have to be a hard bump.

I had one that if you walked to close it went off, lol!

Still didnt matter! You dont want my opinion on this...yes it can be done, but if someone wants your ride bad enough and have enough experience, they gonna take your ride.....K, guess I left my opinion.

I had two of them.......still lost my car and over 5g's in audio, 2g's in rims and a sharp car to boot.

Best security, watch where the hell you bump your ish and dont have a car sticking out like a sore thumb. Been fine since doing those things.