You will need to replace the coil which sits above the furnace. The reason for this is you want a matching coil and condenser, and the new unit uses a different refrigerant (R410) than what your old unit used (R22). I also recommend replacing the lineset (copper tubing between the coil and condenser).

What is the age and condition of the furnace?

Furnaces are Trane units that are 15 years old as well. They have not broken down in the 2 years I have lived here. This is the 3rd breakdown for the AC units however. Can I replace the furnaces at a later date?
Thanks,
Jeff

Replace outside condenser and matching indoor evap coil. Unless you have VS blower on furnace, stick with a good 13 SEER condenser. Does not have to be Trane. Your choice.

IMO