Why do you put higher octane gas in a turbocharged car?

Another way manufacturers look for cheap ways to add more power with a turbo is to make a high compression engine. The head is milled so that it raises the compression so that regular will no longer work. Supreme is a higher octane this gives more power, and also helps the turbo to work better with the output of the engine. IN reality that extra 20 cents a gallon is peanuts. It takes 20 gallons to add up to 4 bucks, thats about a gallon of gas, think about it your talking about maybe 20 miles a tankfull of less driving. Not that big of deal, compared to regular can destroy a 10,000 dollar engine if its used in a high octane car.