I had a Carrier Performance 93, 80,000BTU, model 58mtb installed by
Sears for $3K. The job seams to be a good installation. They installed
2 PVC vent pipes which are pitched back towards the furnace. They
installed a 'media box' which houses a fancy 4" thick furnace filter.
They installed a new thermostat.

But they did not install a PVC liner in my existing metal chimney for
my gas hot water heater. Was that necessary? The installer said no. He
said they used a PVC liner with in a brick chimney with a clay flue
but not in a small metal chimney (B-Vent?).

Was $3,000 a decent price? It still seems a bit high even though I had
one other estimate for $3,400.