For those of you that are constantly mulling over fixing your A/C or convertting it to R134-a this might be a simple solution to get your interior temps down.
This added coil brings my 912e A/C temps down to 34 degrees out all the underdash ports once the system starts getting a good supply of air passing over the extra coil under the car.
Once the air flow brings the system temp down it pretty much continues to work even in traffic with little or no air flow for short time frames.
http://www.engineceramics.com/vw/undercoil.jpg
My system still uses the little 5.5 cui Mini-York compressor and the R134a refrigerant.
It works just great.

Stan Wilder