Here's the official results if you want to see what the other cars were doing.
COMSCC Watkins Glen Results 9-13-2011
As a general guide to the classing and modifications allowed (grossly summarized)
Showroom Stock: No changes allowed except for oil cooler and tires.
Street Touring: Some light modifications allowed (coilovers etc), no engine mods, stock brakes within manufacturer series.
Street Prepared: Open engine mods, swaps, tuning, upgraded turbos, brakes - number of cylinders must remain the same else you are bumped to the next letter class. Dash must remain intact. SPA - 8 cyl or FI 6, SPB 6 cyl or FI 4, SPC 4 cyl or rotary.
Prepared: Anything goes, same letter classing as Street Prepared.