Your car techically calls for premium fuel. If your head had to be shaved the compression will also rise as a result, thus even more reason to use premium fuel.
This topic has been discussed many times, with many pros and cons.
Some buy mid-grade fuel of good quality.
Whatever you do, be sure to keep a window open under acceleration and listen for pinging. The tell tale sign of pre-ignition.
I have found that after using mid-grades etc, the cars all run better with premium.
'03 E320 Wagon-Sold
'95 E320 Wagon-Went to Ex
'93 190E 2.6-Wrecked
'91 300E-Went to Ex
'65 911 Coupe (#302580)