I have two BMWRTX-C alarms and both work OK. Installation in easy and the remotes have a good range. I am having trouble adjusting the tilt and motion portion of both alarms. The lock, window rollup and sunroof closure work just fine. I have a small problem with one alarm in a '98 M3 that I think is a bad switch on one of the doors, hood or trunk or a bad connection at the plug-in harness. I need to check these before making a defective unit call. The Stellar/autoloc tech support leaves much to be desired, BUT you can call and ask for engineering to get more complete answers. It seems tech support calls them anyway, you might as well talk to them directly. The features of the alarms are all there, but their feature list and descriptions are somewhat liberal in what they actually do. I think any complaints about the system need to be tempered with some level of mechanical experience of the installers/users. I haven't had any of the problems I've seen described on the lists. I haven't tried it yet, but I believe that the alarm's lockout features work throught the car's EWS so that once the alarm is set, if the unit is yanked out, the car still can't be started. Still evaluating, though. I wouldn't make a call on whether to go Stellar over BMW to anyone just yet. I do like some of the features of this alarm. I have no experience with any of the other alarm systems.