I know this thread is a little old but in San Diego S2000's are very competitive; especially in stock and street tire stock.
I had to borrow an S2000 when my vette broke a power steering hose and ended up taking 3rd in class out of 14 drivers. 1st went to the owner, 2nd to another S2000 and then me.
http://www.sdr-scca.com/solo2/result...02-fin.htm#sk1
At above site scroll down to SK1 Street Tire Class and you'll Jeff C in first and Jim O in third and four out of the top 5 are S2000's
I was so impressed with the car I bought it the next day and now have my vette up for sale.