The best way to figure out where to shift is to get your car dynoed and look to see exactly where max TQ and HP are to determine the best place to shift. You also have to determine what type of driving you are doing. For normal driving there is no need to ever exceed your max TQ RPM range. Also as the engine wears your power peaks will move. Ive had my car dynoed 2 times sofar with only 1700 miles on it, at 1700 my max TQ was 250 RPM lower than my first dyno and has much more duration, max HP was 250 RPM higher and also has more duration. The way my dyno graph reads I probably dont need to take my car over 5200 RPM. but the best way to tell is off of a dyno sheet, and each engine will be different.