The color options are different. But that's personal preference. '02 does have a few tweaks, but not enouhg to matter. A good deal on a '00 or '01 would be better than paying extra just ot get an '02, unless you really like the color.
Not quite true.... The 2002 received 130-something changes over the 2000-2001. Among them, slightly different upper bodywork, braced swingarm, different carbs (back to 98-99 spec but with 1mm+ float height), and a slightly heavier crankshaft for smoothness. The 2002-2003 also have a 6" rear rim; I think they were 5.5" before...either way you can still use a 180 or 190 - your choice.
Having ridden a 2000 and my own 2003 stock (which shares all but colors with the 2002), go with the 2002... It is MUCH smoother running, with better throttle response, though slightly (like 1.5 hp) less steam on top. I didn't find much difference in the handling, though I felt the 2003 was slightly nimbler. Either way, both are very stable. The main thing is, you won't have to rejet a 2002-2003 for smooth running with clean throttle response, which you will the 2000-2001.
Thanks for all the input! I ended up getting a 2002. It only had 4500 miles but had a lot of sputtering while just on throttle (cruisinig). A friend shimmed the stock needles and that seems to have improved it (it has a Yosh RS-3 bolt-on). The K&N seems to help too, but I still have to get the lower RPM's smoothed out...under 4K has some stumbling.
I am planning on getting the KLEEN system blocked off, +4 ignition advancer and some carb tuning done today. Also, I'll drop a tooth in the front.
Is it worth buying a full exhaust? Will it improve performance? I have been eyeing some used Muzzys and a Hindle on eBay...
With the mods you're planning, add in a jet kit sooner rather than later. Ivan's is the best - the slightly vibey nature of the engine at low rpms will be gone, and the throttle response will be very crisp - a lovely improvement to the bike.
Most performance reviews I've seen of the ZX-9R say the 2002-2003 header design is excellent, and there's little need for anything other than a slip-on to see noticeable performance gains. Ivan's plus a Yosh RS-3 slip-on netted me 9.5 horsepower on top, +4-5 throughout the rev-range. That said, if you spend the time on a dyno, I'm sure you can get a full exhaust to help you a bit more than that.
Though Muzzy is a Kawasaki tuner, a used system from them is best avoided, in my opinion. Those I've seen have needed some bending mods to fit well, are very loud, and have very thin wall piping. The thin walls are great for weight reduction, bad for a robusticity. One friend had to just replace his cannister after setting his bike down on it in a parking incident (< 2mph), as both the lower and upper seams on the cannister broke on his Muzzy. I don't think that should happen. He replaced it with an M4, and was happier than with the Muzzy.
If the Hindle has low miles, that is a good choice.