I talked to my buddy Aaron @ Tony Stewart Racing, and he said that it is mainly a race equipment and service related event. For example, there might be companies that do vehicle wraps and graphics, race trailer manufacturers, marketing/promotion reps., race car parts (ex. radiators, helmets, tires, etc.).
Tony is a Co-Sponsor with some other race affiliated companies. I know that C&R Radiators was one of them.
He said that it is in no way anything like a SEMA knockoff or anything like that. No custon rides, or manufacturers showing off anything, but just displaying their products and services to the racing industry.