Thanks everyone for the encouraging words. We're on the southernmost tip of Texas, with my office literally on the border/river, so having an alarm is something that is actually 'elective'. If someone takes a car and gets it across a bridge (easier to leave the US than to re-enter it), then all the fancy alarm systems in the world mean diddles. It's mostly for our own peace of mind. We have it garaged and my parking spot is in our storage yard a few feet from law enforcement. It's just that as a former New Yorker, I want an alarm system.
As for the local mechanics, in the mission to restore my little Datsun, I've had to learn how to read electrical schematics and I re-wired the body harnesses, though I know better than to tackle anything like the setup in the Bimmer. I just also learned the hardway that being a woman (and this is not to talk less of dealerships) tends to have mechanics think that I'm an idiot and I won't question their estimates of what could be wrong with my car. In the past, this has saved me literally thousands of dollars in unnecessary repairs. I just like to deal with car repairmen who at least respect the fact that I am interested in my car and how it works, especially since my husband, a merchant marine engineer, is away at sea more than home and our cars tend to misbehave when he's away. The BMW dealership also is co-partnered with the Toyota dealership which I've already had several 'dealings' with regarding our trusty old 4Runner, so I'm pretty familiar with the guys, just not with the 'BMW stuff'
I'm going to check the websites listed for the alarm system, and as soon as I get the car cleaned and shiny, I'll post her, plus add a new list of 'what now?' questions I'm sure I'll have.
Thanks again, and I'm really glad I found this site.