I can assure you that your temps are MORE than normal. My 95 M104 motor gets hotter temps than you 93 104.
I have been frustrated with this also. I have gone to a 20/80 mix of MB coolant and water, respectively, and added a bottle of WaterWetter.... but my temps seem higher than ever. I don't know what to do...! I have recently replaced the thermostat... and coolant, but that's about it. And I'm only in So CA! I live on the coast, so temps RARELY ever get above 85.
2006 E350 w/ 155k miles (Daily Driver)
1993 300E 3.2L Sedan w/ close to about 300k miles
2003 E500 Brilliant Silver (Had 217k miles when totalled!)
1989 300E with 289,000 miles (had for <1 yr while in HI)
03 CLK 500 cabrio (Mom's)
2006 C230k (Dad's)
1999 S420 (Mom's/Dad's)
2000 C230k Sport sedans
2001 CLK320 Cabrio (Mom's)
1995 C280 My First Mercedes-Benz... (155k miles. EXCEPTIONAL AUTOMOBILE. Was Very hard to let go of!)