Imrans graph is certainly interesting but as he points out it is not a scientific test.
I've come to the conclusion that for me there was no noticeable power difference with my 330i because either I didn't use the V power for enough fill ups, listened to an engineer who said quite rightly imo, that the engine isn't really that high on power output/state of tune and the dealer who said don't waste your money basically.
I can certainly see the 'cleaning' benefits perhaps.
Maybe I should run the S5 on 95 RON for a few tanks and see what happens............or maybe not. I don't want it to be any slower tbh, so I'll assume the V power defo. helps in my current lump. Or is it all 'auto suggestion' as has been said before on previous threads of this nature...........who knows. I want it to be true because of the cost of the friggin stuff. Bloody Government.
Maybe we need some more dynos.....would be interesting.
Edit: I've just remembered that when I test drove the M3 last year I specifically asked the sales guy whether the M3 should be run on 98 RON all the time as having the Porka T that should have 98 RON. Sales guy said to just fill up every fourth tank with super unleaded and run it on 95 RON otherwise. Personally, I didn't hold with that view for the M3.