I rebuilt the two rear subwoofer speakers on my SRT6 coupe using this kit . . .
https://www.ebay.com/itm/2-6-5-Butyl...0AAOSwCU1YtyvX
This is the second pair of subwoofers I've rebuilt. It is not difficult and the 13 year old subwoofers work and sound like new again . . . An inexpensive fix for this inevitable problem on all Crossfire subwoffers . . .