Thanks for the replies. I would just get a refoam kit, but what first brought this to my attention is I heard like a vibration sound coming from the sub when I was playing music a little louder than normal The sub was only turned up 1/3 of the way, so I couldn't see how I would have blown the speaker but then I noticed the foam crumbling.
Would this foam crumbling, causing less support make the subwoofer make distorted sound?
I can replace the foam for $25 or get a replacement woofer for $25 to $38 + shipping. Should I just get the replacement woofer to be on the safe side?
This is the reason you don't borrow someones elses old equipment, because if it breaks your responsible!!!!