I recently had a PPI done on a 93 500E and the compression results ranged from 155 to 157. This was in high altitude and as I understand it air density is less at high altitude thus lower numbers. Anything below 150 would be something to worry about. A really good engine would be around 170 near sea level.
I found this information on an earlier thread , if I find it I will post it for you to read.
By the way I never did get the 93 so I'm still looking too.
Good Luck and I hope this helps.
02 C32 AMG
84 190E 2.3 5 Spd