I sell hypertech, superchips,edge,bullydog,and sct and i havent had alot of problems with any of them. There are always some bad stories with any products you buy. What mode do you have it set on. And yes it is better to run premium than regular. Unless you are looking mainly for horsepower one of the programmers will not help gas mileage much at all. They have programmers that are more for fuel mileage but its just a minimal increase.