What they don't say is that they are cattle pooh
There have been numerous tests carried out in the UK by recognised groups such as the VVCC, RAC, AA etc and mags like practical classics. Most have been reported to the advertising authorities in the uk and now you don't see any adds for them anymore....
This includes the "special alloy of tin and other rare metals"
methods of "magnetising" the fuel and other stuff
Tip a bottle of injector cleaner, octane booster, or even lead replacement stuff in you tank now and then if you want to
I guess you mean the Shell product OPtimax which is a higher octane rating (97 RON uk) than the usual unleaded (95 RON).Trouble is here the quality varies badly. I know someone in the Scottish rally fraternity and he had a Subaru engine tuned and set up to run on it. Next rally the engine blew up! Fuel sent to be analysed
and it was "way off". The standards have lower and upper limits as wide as a barn door
Hence I use "Carless" fuel which is formulated very exactly and is equivalent to 99 RON unleaded, and still chemically meets the standard for road fuel which is all you can use....
Mind you at over £5 a litre I don't use it every day [:p]
Malc