Trust me USE the Premium .... This is from a friend Sam who Also happens to be a service manager at a dealer
"The MINI's seem to be good cars & long lasting, but run hight test gas
of good quality in your MINI. I've seen MINI's coming in carboned up. Some so bad that one of the valves do not close all the way. That leads to a burned valve. While your MINI will run on regular it's the regular fuel that leads to those carbon deposits."
I told Sam that I add a bottle of Chevron Techron at every oil change.
"Techron is good stuff, but use a good quality high test fuel too. Shell, Marathon & even BP now have additives in them to keep the valves clean. Shell is the best"
There you have it. Some good advice from someone that I trust. I know some of you run regular to save a few cents on fuel. You do so at some risk it seems. You will never save enough money buying regular to pay for the potential damage it causes,
Motor on, with high test!