I know that if I want to be guaranteed the best chance of winning at the lowest cost, I'd buy something japanese, sufficiently cheap and reliably fast. You can pick up a 63 second R6 for under 5k.
But I did the supersport thing a few years ago and it was fun but not as fun as throwing the SD Dow the track. If I want to win here I have to go up against Daniel stauffer and I know who'll win there. I'm more concerned with fun and the challenge of something different.
The only thing I don't want is to bin my beloved Helga on the track. So I need a pure race bike that I can bin, pick up, tape up, and ride on. And if I'm buying a bike for the track, I'd like it to be the best starting point I can... If that means another 06 I'll do it. But if an SDR can get me a little closer while still keeping it fun, well that's the best of both worlds.