Thanks, my "great questions" are the result of not having enough money to worry about legitimate (but expensive) upgrades to my car, so I see if I can inexpensively utilize the existing functions of my car (as in fixing the power headrests).
There's no LED between the front seats, so I assume that the mirror LED is either dummy or for a non-installed alarm, as you said. My car is also prewired for a BMW CD changer, but cheapskate previous owner did not apparently get either item when he paid over $43,000 for the car in 1990.
I'm considering getting an $89.95 Stellar keyless entry for my car from Bavauto. It worked great in my 528e, and I remember there was a third button that could be utilized for another random electronic function (dome light, parking lights, etc.). Maybe I could tie this light into the system. All I'd like is for the light to flash when the car is locked. Anyone who wants my car and knows what they're doing will be able to have it, despite any alarm. But with the flashing red light, ordinary people will think I have an alarm (plus it just looks cool), and that's all that matters anyway!
///Thanks!