I did some looking on their website and found this:

Classes Run on Street Nites Trophies in all bracket classes
plus $100 win / $50 r/u (12 cars minimum to make a class)

Pro Street ( Bracket 1/4 Mile )
Helmets, Mufflers, Slicks Allowed, Street Appearing
13.99 and Quicker Cars

Modified Street ( Bracket 1/4 Mile )
Slicks allowed, Mufflers, Helmet, Street Appearing
11.00 - 19.99 ET Breaks

Pure Street ( Bracket 1/4 Mile )
Licensed and tagged, Mufflers, No Motor Modifications
DOT Street Tires

Import Street ( Bracket 1/4 Mile )
Tagged and Insured , Mufflers

Street Bike ( Bracket 1/4 Mile )
Tagged & Insured Mufflers No Slicks

OUTLAW KWIK 8 ( 1/8th mile ) Car & Driver $50
Heads Up 1/8th Mile
NHRA Safety Rules
Mufflers or Turbo
$1000 win
$300 r/u
$100 Semi

8 Car Minimum