Currently I have a Carrier Infinity 2 Stage Variable Speed Gas furnace with 2 Speed Infinity 18 Air Conditioner. If some day I decide to upgrade to the two speed Heat Pump what else may need to be replaced besides the outdoor unit? Lineset? Evap coil? Would this be a fairly simple labor job for a service tech?

Last Question: What would become of my 1 year old 38TDB? Is it possible the dealer would want to buy it back (real cheap)?

Furnace: 58MVP80-14
Coil: CK5PW036
Condenser: 38TDB-3630
Infinity Stat

Would like to replace 38TDB with 38YDB or next year's more efficient model. With gas prices getting higher I'd like to check my options.