The voltage regulator is a $20 part and is easily replaceable. You're farting in the wind if you skip that step. Unless you're running some insane stereo or enormous electric fan, 90A is more than adequate for a W201.

__________________
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]