For me, the strength workouts of P90X are the program's best aspect. I like Kenpo (not the warm-up, do that last as a stretch), but not the other cardio workouts as well. If I were to combine, I would use the X strength and Cathe cardio. Also, I would add in or sub a Cathe leg workout as the X is light on leg work. Either just sub for legs and back or just add in an additional leg workout as legs and back is a good workout.