Amp getting hot.....lights dimming....and especially if you notice batterry voltage low when doin the boom thing... i am not sayin it will stop your issues, but it will enable your electrical system to do ALL it can.....next thing would be a bigger alternator or a \nother battery....or both...and also, limit your volume...a stock electrical sytem can only do so much!
Lights dimming...check. Hot amp...not so much. I talked to someone from kicker today about one of my subs, it has been making a weird noise. I mentioned to him over-excursion (because thats what I Think it is). He said "could be" then he forgot all about it and mentioned to me the big 3. This noise does increase as the volume goes up. I can't figure it out.
i say scratchy coil cuz it does it at low volumes and gets louder with volume increase.. a sub going past its limits will usually only make noise at very high volume.. and will make a clapping sound kinda when it bottoms out.. if it makes the noise all the time its prolly a coil.. sometimes an enclosure will fall apart and make noises too though..