need speaker mod/repair help

I lost a 61/2" woofer in a psb Mini-Monitor to some type of power surge. I purchased them used and they are no longer under warranty, that I am aware of. Are there after market woofers you can recommend that would provide better sound/detail/imaging? Will a dealer sell repair parts or are they going to want to service it themselves? What should I know before I remove and attempt repair? I realize I will have to replace woofer in both if I go other than psb.