I just bought a 2000 last weekend. There are specific part numbers to watch out for on the harmonic balancer. They are:

112 035 00 00 up to 112 035 06 00

If you have one of those part numbers, you could be looking at a problem. It is an easy thing to replace, apparently, and Phil has them for about $50 on this site. Apparently you can see cracks in the rubber, and in some cases you can see the rubber starting to work its way out of the pulley. Lots of stuff on this problem on the site. My mechanic verified it is the original balancer, so I'm just going to have it replaced so I can forget about it.

As someone pointed out, the 00 has more airbags than the 98. As well, the 00 came standard with ESP. These were influencing factors for me because the car is for my wife, and she'll have my one year old son in it every day.