I have 3 Factory A/C systems. One uses R12 because I bought (2) 30 LB tanks when AutoZone stopped carrying R12. Two use 134A, with everything STOCK including the drier, compressor, condenser and expansion valves.
I just have an adapter hose that lets me use my old guages with a 134 tap, so everything still looks stock at the compressor.
All 3 blow very cold just like they should. The only difference is that the systems take a lot less freon before they are full.