I have sxp with awd. I have 550 miles on it now. Took it for 400 miles of interstate driving averaging 75-80mph on sport mode. Got about 24 mpg. Last 200 miles were a lot of up hill driving.
The owners manual states, for the first 600 miles, drive between 2,000rpm and 4,000RPM, SMART OR SPORT WORKS per the factory. By the way I do the same speed on the interstate in smart and the read indicates between 25-26, mine is FWD.