On the anti-blowout kit, after I installed it, I've mowed a couple of times, and I went from the side screens to being almost covered with grass clippings, to about 3 or 4 blades of grass on the screens.
I have alot of rocks on my property, and I'm going to get a 48 inchbox blade to help me loosen the rocks up, and help me make a 'rock' pile. (too bad I don't have any teenagers to help with this one).