The owners manual for my 103 calls for 91 octane.

Many posts here have indicated that mid-grade is ok.

In my area we have 87-89-93. I use 93.

The difference in price between 87-93 isn't worth the damage(long-term) that could be done.

For me, it just ain't worth it. I plan on keeping the car until someone takes my drivers license away from me.

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"