I recently saw A Fifth Gear test on super fuels like Shell V Power. The conclusion was that benefits were minimal. Some forums also claim that any improvements are due to a placebo effect. You paid more so you expect to feel the benefit. How to make sense of it all.

My observations are that surely any test to be worthwhile should be done over a year say. I know that a colleague at work complained to me that his car was running extremely roughly. I advised him to use V Power and he said the car was now running perfectly. My question though is has there been any long term studies and would I benefit from running my Alfa Giulietta TCT on V- Power?

Thanks