i went 2400 miles on FF and put in 2 qts of M1 0-20 and 3 qts of M1 0-30. The car is getting 36 mpg and hopefully as engine breaks in i will be getting 38mpg once i can start putting in the summer blend gas. 6 speed auto. the car is very roomy and and gutsy, i would recommend a sonic to anyone. 0-20 is a little thin but i think engine will survive...i have had 7 new cars over the years and none of them have ever burnt oil, inexpensive cars and expensive oil is my motto. Actually with all the rebates or if you wait for discounts/clearances it is easy to get cheap synthetic oil which is what i usually run.