There has been some talk about this series in the open discussion forum, but I'm wanting to know if I have P90X, Muscle Max, the Pyramid workouts, Slow and Heavy, all of Jari Love's except the first, Slim Series, etc. why would I need the Gym Series? I have some money set back to spend on workouts, but I want to spend wisely, so any feedback would be greatly appreciated. What makes these worth the investment and how are they different from what I already have? Thanks.