[ddsmith]

Shawn,
Since your starting from zero. I would strongly recommend using the factory evap, TXV and POA valve readjusted to the proper setting for R-134A. I did the aftermarket route and I regret the choice. The evap on the factory truck is bigger than the aftermarket units. It can transfer more BTU's meaning cooler cab temps. It also keeps the factory defrost and heater which is a plus. I currently have no lower heater vent outlet because of the aftermarket setup. As for compressor and condenser I would probably use aftermarket units. The benefit of the POA setup is that the compressor continues running and the POA modulates to maintain the pressure and temp at the evap just above freezing when in the A/C mode. This provides the coldest air possible with a large air flow.