I have an '01 KX250, it's torn apart in my garage right now due to blown crank bearings! The motor was very strong and hit pretty hard too, but it blew up on me after 38.1 hours on a complete engine rebuild!!!! The KX line around the 99-02 era were notorious for "falling apart", reliability was dodgy at best! It was a fun bike to ride, but I spent way too much money fixing things on it that should last for a very long time!
I now have an 02 CR250 that runs awesome with the new Keihin PWK carb! It handles a lot better than the KX too.