It sounds like your charge is wrong. Return your electric fan setup to how it was before you changed anything and see if your performance returns. 20PSi suction pressure sounds like a low charge or a pinched off expansion valve, even on a cool day you should be seeing 25-30PSI if the cabin is pulled down, fan on low, and coil cold. More than likely the extra airflow over the condenser sucked all the heat out of the system and it now does no work.

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Current stable:
1995 E320 157K (Nancy)
1983 500SL 125K (SLoL)

Gone but not forgotten:
1986 300SDL (RIP)
1991 350SD
1991 560SEL
1990 560SEL
1986 500SEL Euro (Rusted to nothing at 47K!)

Gone and wanting to forget:
1985 524TD 167K (TotalDumpster™) [Definitely NOT a Benz]