http://hsrrace.com/HSR/HSRHome.nsf/a...b/EJEN-6BHKNF/$file/Spectator+Schedule+-+Mitty.pdf?OpenElement
This PDF file is the spectator schedule. It has some errors, but shows the individual groups.
Group 5 is muscle cars=cool
group 6 is GTP cars = really fast
group 7 =sports racers like Can Am = my group
group 8 = Winston Cup cars= loud and fast action.
See you there