Haasman: I have been using mid-grade (89 octane) for years with no detonation/pre-ignition problems.
Larry: Oil problem: yes, I had oil consumption problems earlier and had the valve guide/selas replaced at 110K. Since then, the car never drank more than 1/2 liters between oil changes.
And I resent your comments about the performance level of a 260E. It has as much accelerating power and brute force as a.................well... a loaded 1976 Pinto station-Wagon with an automatic transmission.
JackD