Air Conditioning

Edit:
What is the difference between Vintage Air's Complete kit and Evaporator kit,

EVAPORATOR KIT: Air conditioning, heating and defrost combination units are designed specifcally for your vehicle and mount to existing holes in your dash and firewall without drilling* or fabrication. Original deluxe control assembly in your dash connects to and controls this unit. Evaporator kit comes complete with all mounting brackets, hardware, louvers, duct hose, wiring harness and installation instructions.

$529

COMPLETE KIT: This system comes with all of the above plus compressor, condenser, mounting brackets, standard drier, pre-formed lines and mounting hardware and attaches to existing radiator mounting holes. No drilling* or fabrication required.

$1199

Cooling wise, and installation wise? I know that it takes the place of existing heater box but does it take up any other space under the dash?
 
By your desription the Evap. kit does not include any of the under hood components so you would use your existing components.
If you get the Evap. kit make sure that your compressor and condenser coil are matched to the evaporator coil in the kit as far as capacity (btu's).