As other's have said the higher octane fuels can be required by older high compression engines or offer a small performance advantage to modern ECU controlled engines with Knock Sensors. These allow the ignition to run slightly more advanced to the benefit of power and performance.
For the M3W I doubt (and have never felt) any performance benefit but tend to use V-Power or equivalent where available as these fuels have an enhanced additive package which helps keep the fuel system and injectors clean.
As an aside, Formula 1 rules specify a minimum of 87 octane and is typically around 91 octane so octane rating itself is no guarantee of performance.
