gas type

If it calls for premium gas you should use premium, a lower grade of gas could cause detonation or pinging due to a lower octane rating (to be honest my own car calls for a higher grade of gas and I have used mid grade for years). The engine has a knock sensor that would retard the ignition timing if it sensed a problem. In theory the engine could run a little hotter power may decrease and mpg could drop a little but I tried on my car with premium and mid grade and so no drop in mpg.