I had the pleasure of owning both models, and let me tell you they keep getting better, stronger, quicker, faster and handle way better.
The 02 S3 was a great bike it did everything I want it to do, Track, mile long wheelies, intimidate other bikes. My only complain was that the steering head bearing required a lot of frequent adjusting (yes many wheelies)
The 05 S3 does everything better, improved power delivery, handing and suspension and it wheelies a lot easier, it is also a lot better track weapon and I have not had to adjust the steering head bearing once.
They are both great bikes! Ride them both, it is up to you. You can always get the 02 now and trade it in when the new S3 arrives. Hope this helped.
BTW Welcome to RAT!
Ton Up!