As for the noise, I had the same issue with some Alpine Swr-t10's. The plastic spider would crack, causing a rattle.
After replacing it (old gf's brother's truck), I told him to go easier on it. Second one didn't have an issue, but I also turned the gain way down, removed his bass boost knob, and told him when it is cold to not beat on them.
The SD3's noise sounds like just internal failure or separation of the spider/suspension issue.