Try Roger or Jeremy from Horsepower sales, the Moroso Corvette Challenge tile sponsor. They may have some used ones, or at least a good price on new ones (tell them Tracy @ RevXtreme refered you). Drag Radials may be a good option depending on the power you make.
I urge anyone in the area near Moroso to attend the challenge races....they are a blast! A gal, Liz (OhyeaLIz on the CF) won the RevXtreme Challenge today at BMP!