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The concept of diminishing returns applies here. Certainly not worth it in my opinion. I think I run 91 and have had no issues. Also I have not seen anyone on this forum with better fuel economy. My daily commute gets 30+ mpg to gallon in comfort. 27 in sport+
Ive used 91 oct and 94 oct and seems the same to me. Without a tune it wouldnt matter.. It just happens that 94 oct here is sometimes almost the same as 91, so depends which gas station im near at hte time.
Dont think it'll matter much but for $0.03/liter, its not a bank breaker either. Get a tune and that'll be a good excuse to use 94 Oct
I've read in other forms that some Porsche Turbo model registers less pinging (and timing retard) on 94 vs 91, according to a data logger output. One wonders if the same applies to the C43 which is also a turbo model. But in all fairness, the Porsche in question is designed for 91 minimum / 93 preferred.
MB just states a minimum value of 91, and this in my opinion leave lots of room for speculation.
See below,
This is from New Zealand where 98RON is specified. This is more or less equivalent to 94AKI here in North America.
I really believe that they purposely state 91AKI as the bare minimum in North America because 94AKI is more difficult to obtain in some US states, and Canadian provinces.
In theory it will make a difference to the power output. I run mine on 95 Ron (UK). The adverts for fuel that say 98 will improve fuel economy is bollocks. Its all about power output. Some cars have octane sensors that will delay the timing but who knows if the C43 has one.