I ran mine for a year on 95 ron with NO problems, I also ran it on 95 ron after I had it mapped with NO problems.
I have tryed BP Ultimate and it ran like a bag of s**t. I now use Sainsbury 97 ron and it run's fine, personally I dont see the point in paying extra for overpriced fuel.
your ecu will adjust to the fuel and run accordingly after a couple of tanks.
petrol with detergents in it is worth the extra in terms of engine health imo. my engines always had the posh stuff but showed very little wear after 90k.
also car goes faster
and you get better mpg too, so its not as expensive as it first looks.