For Race Experience Events, cars need to be prepared for wheel-to-wheel racing — roll cage, racing seat, and harness at minimum — and stay within a general performance cap, roughly comparable to SCCA Sprint Road Racing Touring 2 or about a 7:1 horsepower-to-weight ratio. Vehicles need four wheels and a low center of gravity, and most purpose-built or professional racing chassis (TCR, GT4, carbon-chassis, big-bore tube-frame cars) aren’t eligible, though some exceptions exist for cars like Spec Racer Ford.