I believe that what riff was commenting on, the center panel, does change the way I fly my Phoenix kites. Most of our team maneuvers are indeed initiated from the center of the sail. Keeping pressure in the center keeps the whole sail loaded, IMHO. I look at pressure as a ball, I don't want to lose it as I turn. To me, venting the center is like taking the engine out of my car. Now I admit to not flying any center vented stuff, and I won't mind trying anything that is.