[dahappybanana]

Now I have no clue as to if the gas companies state the correct octane level. They should by law I believe. The difference in octane is that higher octane rating means it takes more pressure to explode then lower octane.

Now I believe all new Mercedes have a sensor that if it detects lower octane then it will restrain the engine enough so it does not knock. That is why most people can't detect a difference.

If you really want to see the performance differences take 3 cars and run them on the 3 different octane levels of the same gas company and run these 3 cars on a dyno and see what happens to the performance.

The reason for using high octane in cars is due to the fact that some cars have a 9:1 compression ratio or higher, thus if you drive hard and floor it often like some of us do then the cylinders will pre-detonate, misfire, or knock.