I did the rebuild kits on the sub woofers and one fixed and the other didn't, blown coil. I went to my local audio place with the XF parts and he tells me the current sub woofers are Dual Voice Coil, DVC, 2 ohm speakers, and it would be difficult if not impossible to replace. I have reviewed most of the threads on this issue and have googled the recommended speakers that are a "no modifications required" variety. Some speakers are no longer available. I cannot tell if any of the recommended, "this is what I used with no modifications" list, was adherred to in the 2 ohms and DVC my audio guy said I should use. I will not modify the housings with the exception of enlarging a mounting hole. Thanks for the help.