Originally Posted by MRAMG1
Also keep in mind that you will actually LOOSE HP due to higher octane fuels as the flame propogation is slower, aka it burns slower so you loose efficientcy. Anyway to each his own, but if your car isn't tuned, or doesn't require it, bumpnzx3 is right and your just burning up your wallet.
This is true for cars without a knock sensor, but our cars dynamically adjust for knock and advance timing as better fuels are used. Now, at a certain point there are diminishing returns, but since the fuel is so bad and the air is so damn hot and dry (thanks ohlord), better gas can make a difference.