Great advice from everyone. Classing is SCCA based, something to keep in mind. The cars allowed in each class do not take into account the mods you may or may not have. It is one size fits all. Race compound tires are generally equal to about a second per run. There is a learning curve to using race compound rubber and that first run may not have the tires up to optimal temperature range. The large amount of competitors may be so big that the tires cool back down to suboptimal temps between subsequent runs. I think one or two people use race rubber to eek out that last second and pad their raw time placings. Otherwise Dunlop Star specs have great stickiness in dry conditions, okay traction in moist conditions. They also have great longevity vs. wear and their heat cycling vs. blistering is superb.