The pricing you were given is nonsense as long as this is a relatively simple replacement. You need other quotes.

Here is my general spec sheet for new system.
both outside and inside units should be replaced to have a properly matched system.

15 SEER, 12.5+ EER, 9 HSPF
best matching VS air handler
full BTUs in both cooling and heating for your rated size
R-410a refrigerant(same as Puron)
scroll compressor preferred
electronic demand defrost preferred
thermostat with "dehumidify on demand" feature
staged backup heat strips
new and correctly sized refrigerant lineset
10 yr warranty on parts and compressor

you want a thorough inspection of your ductwork system. size, overall condition, supply and return lines, insulation qualities, leak test, etc.

any hot/cold spot issues in your home should be addressed.

My personal recommendation is Trane/AmStd, Rudd/Rheem, and Carrier/Bryant.

Depending on your location, I would not want a new HP system without electronic demand defrost that eliminates and reduces unnecessary defrost calls not to mention the cost and wear and tear to condenser.

IMO