Bold for emphasis. It's there, and it's free. One click and voila. I don't use it all the time, because then it would get predictable.
Anyway, I hear ya on weight, and it IS meaningful.
All's I'm saying is that I don't think I'm going to seek weight reduction from stereo equipment. I would be far more interested in choosing audio components that achieved the highest possible sound quality, rather than choosing them based on their lack of heft. (For example, bigger magnets in speakers often result in richer sound.)
PS: 16" wheels are lighter than 18" wheels, but you don't see many folks choosing 'em for their E46's these days! (Even if they cleared the brakes!)
PPS: I don't have a sunroof, and I have manual seats. That's gotta save a few lbs. right there, no?