It's mentioned in the manual for use when you don't have access to good quality fuel with additives.
Ok, I confess I still haven't had time to read the Ed. 30 manual, I just read the GT Sport manual when I bought it (at the end of 2008).
So, BGK44 is supposed to be better for the engine than this additive, for example? I have no idea...
I've only used BP Ultimate 98 RON so far but I've just owned it since April and haven't had the opportunity to use it much. Currently there's no Shell V-Power in my country, since Shell sold all their gas stations to Repsol.
So far I only saw 1 misfire when cold in one occasion and the engine behaved well in dyno test.
My surprise was the inlet manifold and valve stems were pretty choked with charcoal though. It's now being sorted while a RFD kit was fitted.