well - I have just gotten quotes for a 2 zone replacement of air
handlers and condensing units (ie 2 new condensers, 2 new air handlers
+ pipework, limited duct adaptation)

The best price I can get for the Carrier systems is $13,586

In 1998, we had 2 Carrier Heat Pumps put in our new house. A 3.5 ton and a
2.5 ton with FK4CN var spd air handlers and full insulated hardduct in a
2800 sf one level home. It cost right around what theyre quoting you now
for your job but yours already has the ductwork.