Found some interesting stuff on the fuel debate today, this is a summary semi- plagiarised
h34r: from a couple of hours looking Last night regarding Vmax -
{Vmax is as Fahad correctly points out is different from any other premium diesel (not petrol now) in that it is a Gas to Liquid fuel process.
Converting LPG to diesel to produce synthetic fuel, but it is not pure GTL only partially refined, but at the moment at least, the most refined diesel and a lot greener than any other.
They still add additives to clean injectors etc. like any other premium diesel, though.
In addition, there is a debate apparently that as diesel lubricates, a bit like a 2-stroke mix, V-max might have reduced lubricating properties, as synthetic , which apparently Shell will not discuss.}
The thing I cannot work out is surely if these premium fuels (whatever the brand) are so effective, at reducing emissions, soot deposits, more power, MPG, etc.
Is Why The oil companies who are not short of money, do not commission an independent through test paid equally by all parties involved, which would prove scientifically what they claim?
Although everyone maybe would not want regular stuff then!!
However, as I have used it even in my 20 year old Landy, which basically doesn’t smoke hardly when starting it must do something good!
Ultimately, just like putting crappy oil in your car or pattern parts vs original it’s comes down to personal choice as Fahad rightly says “Depends what you want from your car and how much you care”
However, I will still stick it in mine, and the Landy, and use millers additive when up in, - say Scotland and premium is not available.
But no-one really disputes the cleaning property's any of them posess over standard fuel, and as the extra cost equals out, with the potentially extra MPG really, the fact the my engine will be cleaner , means it gets my vote!
Here are a couple of interesting threads, 1st, regarding Millers, and 2nd generally about fuel.
http://www.seatcupra.net/forums/showthread.php?t=188065
https://sidepodcast.com/post/sidepodscience-quite-a-challenging-challenge
http://www.honestjohn.co.uk/forum/post/?t=56224