A guy I met has a KG-4 and he bought replacement drivers from a guy in Arkansas, I think his name may be Krites, whose business is selling replacements for Klipsch. He may do others as well but the first guy only gave me so much info. Any way the driver he bought was aluminum and he says it is very good, better than original.

Some how I ended up with a damaged woofer in my Forte, unfortunately, there's no replacement available for it.