Like others on here I had the problem of my rear speaker/s cutting out after a while. Today I took all of the fwd tupperware off the bike to change the air filter and also did the fuel line QD's.
When I went to put the stingray back on I found that the wire bundle with the large round connector on it had been pinched and the tape thet BMW covers the bundles with had been worn through and one of the wires had a very small bare spot on it. Guess what that wire bundle goes to? Yep, the rear speakers (and other items I'm sure). I fixed the wire and recovered the bundle. Then paid close attention to that bundle when I put the stingray back on and routed it differently from where it was. That wire bundle is about 8" longer than the other 2 it runs with and I guess BMW just stuffed it up under the stingray to take up the slack.
The speakers no longer cut out and sound much better (sounded "scratchy" before). If your speakers are cutting out or popping...have a look at that bundle.
P.S. Yes, I put dielectric grease in all of the connections.
Oh, and none of the plastic QD's broke when I removed them, so if my stainless steel QD's ever fail
I have spares