Hey guys, it's been awhile since I last posted, and a lot has happened in and around my Elantra since then. I had a 10 inch Alpine type-S being pushed by a 500 watt amp in a ported box in the trunk. Long story short I ended up frying my battery and nearly destroying the on board computer due to an installation problem of mine.... Anyways, when I still had the sub in the car the back deck (under the rear window) would rattle horribly. It was better with the back seat down but the rattles were still there. Now, after taking too long of a break from bass I want to re-install the sub. Has anybody else encountered these terrible rattles? If so what did y'all do to eliminate them? I've tried everything... I've stuffed trash bags under the deck, I've put a towel in between the glass and the deck, but nothing really helps. Will I need to resort to a sound deadening material? Thanks everyone.