I don't have the factory alarm, but I did purchase an aftermarket from the dealer. It does not have a motion detector, but if someone bangs the car it will go off, and I can set the sensitivity to whatever. The alarm guy set it to be pretty tough bang, cause I have cats so wouldn't want a cat jumping on the car (which they never do, cause there is no hood or trunk) and setting off the alarm.
I did park it once in Hollywood, and when I got back to my car I saw the alarm had gone off. The blue light was flashing like crazy, and the horn honked 3 times letting me know it did go off. The only evidence I saw of someone having touched my car were the fliers stuck under the wipers, I did a test of lifting the wipers and letting them down with out care and sure enough, it was a big enough thump to set off the alarm. GRR I hate people that litter my car with fliers
Anyway, the alarm I bought from the dealer is made by KARR, and I don't remember how much I paid for it.