Premium or regular unleaded?

[Nobody Actually]

If the octane level is all you are worried about why arent you promoting ethanol, with octane levels up to and over 100?

no offense champ but where ethanol is concerned, i like my fuel system un-corroded thanks. premium for me.

 

[nugatory]

I find that using the highest octane + a bottle of that Octane Booster gives the car the response you're looking for. But also with that, you know your car is running higher octane fuel and I tend to drive it a little harder knowing that, but as a daily driver pottering along unleaded seems to make no difference.

If the cars running optimal, e.g. good fuel, good electrics, good motor, then it'll save a couple of km's running the better fuel to keep it running optimal.