Will switching to a better type of gas damage my engine?

Do you mean gas with a higher octane rating ... if you do the answer is "Nope"

No but you won't see any benefit either unless your car pings a lot. You will spend more money for gas.

Higher octane fuel is no more powerful than regular fuel ... The Octane level only determines the speed that the fuel burns at. Low octane is like a quick "POP" but High Octane is like a "POW". That;s why engines requiring High Octane fuel will "knock and ping" if you put lower octane gas in. The High Octane is usually required for higher compression engines that use a slightly advanced timing setting. Putting High Octane gas in a regular engine won't do anything except waste money

Here is a list of retailers specified my nearly ALL car manufacturers. Others do not have the proper detergents you car needs. And Tom I agree, there is no more energy in a gallon on 91 than 85, it's flash-point. Have a look: http://www.toptiergas.com/retailers/