If you are going to always run premium anyway, you should remove the ignition advance setting resistor near the master cylinder for maximum ignition advance.

On Euro cars there is a dial that is used to adjust ignition advance to accomodate the fuel octane. On US cars a fixed resistance is connected in its place. By removing this resistor and taping off the connector to prevent the entry of dirt, you are setting ignition to the max octane setting.

I did this some time ago and it does make a difference in power and will slightly increase fuel mileage AS LONG AS YOU BURN PREMIUM. Don't pull the resistor and then run low octane fuel, you will risk engine killing spark knock.

Have a great day,