I've got a 2000 W202 Mercedes C240. It's got a V-shaped, six cylinder gasoline engine. On the fuel cap, it says RON 95 EN 228. And in the manual also it says "Use only Premium Unleaded petrol". I sometimes want to try RON 98 as it's imported from Europe and everybody praises it. But I don't know whether it would harm the engine. Does the manual mean at "at least" or it means what it says- "only, no lower, no higher"?