[billybek]

6K? Holy crap!
I could see that price if they were to straighten out the supply and return plenums.

Point of reference. I had a 16 year old Trane high efficiency two stage nat gas furnace in the house and it started to get a little glitchy. I could hear the difference in the startup of the furnace and would race down to the basement and try to find what was causing the failure. Can't remember what the diagnostic on the flashing LED. After having my meter and tools parked beside the furnace for about two years I concluded it was a motherboard glitch. NLA and the factory retrofit was almost $700 my cost and I had to re-wire the furnace and change out the induced draft fan and no warranty on electrical parts.
Went to one of the wholesalers we deal with and picked up a new York two stage variable blower for cost and had a friend pull permit for the install. Done. Fantastic furnace too BTW. Highly recommended.