Id go with the 00. What am I talking about, I did go with the 00, I bought mine used. The reasons? 00 had the new carb & shorter backbone sharpend up the handling. It has a bigger motor obviously. The only problem that would worry me now would be the counter balancer keyway on the 2000 models. When they made the piston bigger, they didnt make the keyway bigger on the balancer and it cant balance the extra wieght of the larger piston. The 2001 has the counter balancer drive gear splined. So Yamaha
knew about the issue and solved it, but that doest help the 2000 without buying a rightside crank half and gear. What do you do? Keep a good ear on it and when, not if, when the keyway starts to go, tear it down and make your own keyway. I did. It cost me 80 cents. You can buy the metric keystock, but I hand fit mine to a .0015 press fit.