I've bought quite a few kooks off this forum in the last year
, I agree on the grading you can get some lower end bats that go like stink. I picked up a 350 Kahuna off the forum which a team mate bought off me, he had kook sponsorship deal last season and had a couple of supposedly players Kahuna bats, the 350 went better than his players and is now is main bat. I've got a 900 and 600 Kahuna and tbh they are pretty much the same. You can defo pick up some good deals on kooks on this forum, which I guess is due to the concaving, but from my experience they are good bats, half my team mates are now using them and they all go. The softs are different gravy!