I have used the CIH "Trimble" system for three years and have only used foam one time, the first day I sprayed with the guidance system. The foam will only confuse you or let you see how much lapping you were doing. You won't need the function that tells you when to turn it on and off at the ends since you already know that from years of experience. They are all simple to use and like driving a car you must still focus on the machine and not the instruments. It will come easy. Although I have a trimble I might opt for one with a bigger viewing screen. When I spray with my coupe I must set it outside and then I have a dark box built around it for better viewing. The new, all in one unit, from CIH looks neat. That is all I know. The hills won't creat a problem for you, and the accuracy will make you smile.