my father claimed that his 00 S500 wasn't blowing cold enough and/or wasn't cooling fast enough so I hooked up the R134 gauges and temped the vent temp:

with engine idle (68F ambient) and both climate controls set to LOW/high blower fan

30/130 PSI (low/high side pressures) vent temp 52F

The pressures seemed to be a bit low so we attemped to add some R134 however, with the low side open (not the air, just to the can) and the high side closed the system did not want to take any more refidgerant even after 5-10 minutes of idling...during this time there was no change in vent temp either. I would have expected this car to blow <40F vent temp (especially with ambient only around 70F).

BTW: No rear A/C (or CC unit) in this particular car.

Any ideas??