Contact Jim Smith with Avantgarde. Jim is the importer for the speakers and has been working on an upgrade package. I believe he is shipping it now. You can find his number at www.avantgardeusa.com and at this site you can find his info on the upgrades:
http://www.avantgardeusa.com/upgrades.html
Tao
http://www.avantgardeusa.com/upgrades.html
Tao