I caught this Koni race series with GS cars and street tuner cars all on the same track.
GS cars were BMW 3 series, mustang GT, Porsche 996 and Firebirds. The street tuners had RSX, Acura TL, RX8, miata's and a Z4..............why no S2000's.

Do they race in their own series or does the roll bar have something to do with it?

 

It's classified with rules that would make it completely uncomptetitive in the series. People have tried to get the organizers to change all that, but they just aren't interested.

 

elaborate,

are you saying the S2K is like a tweener between the 2 classes and the rules would favor or handicap it depending on the class?

 

OK, I read the rules and I don't see the S2000 listed at all.

 

This was tried some time ago at the beginning of Grand Am Cup (now Koni Challenge) and my recollection is that there needs to be some cooperation from the factory when classing new cars. When asked, Honda basically said that they were more interested in people campaigning RSX's and TSX's than S2000's and would not encourage the S's involvement in the series.

Another issue is that the way they equalize the cars, is they allow certain modifications (specific part numbers) to different parts of the car. The S2000 has very little room to play with in that regard, there is no modification short of FI that really changes its power significantly enough for it to be able to keep up with the 350Z for example.