I've heard some insurance companies require the equipment to be bolted down to the chassis of the car in some form or another for them to cover it-just a thought...
many companies require purchase of an additional rider to cover aftermarket things like stereo systems, added engine mods, etc.. call your ins. co. to find out for sure. you'll probably also need full coverage, not just PLPD or comprehensive.
Meh, I had my car broken into and my subs and amp stolen about 2 years ago any my insurance covered it. Actually at that time I didn't know anything at all about car audio and had some shitty stuff... but I just had to tell them "what I had" and they paid for everything. And it was especially funny because at the time... my amp was actually blown and not even hooked up. If they hooked it up to a power source it just throws out as much power as possible randomly. I ended up getting a new car with the money I got and a trade in of my old one.