Cooper S boy
Congrats on your new car, plus excellent choise of colours.
I, like you have to travel about 15 mins to local Shell garage that is owned by BMW in my case, so see lots of Cooper S Minis. I live 1 mile from the largest Tescos in Europe but I have always used Optimax as it gives me an excuse to go for a drive. As for extra performance, I dont know, probably not much, but if it does treat the engin better than regular petrol then I will continue to use it.