I don't get it. Why protective mode and the walls in your house cause the speakers to overheat. When the 6k were upgraded to the latest version didn't they come from Atlanta. I am sorry to say this but this all sound very fishy. Is it possible to remove the cards from 6k on site? Who's your dealer?
If you bought the G91A used you paid too much for it.
I hope you didn't buy your stuff from some dude in Czech Republic.