I wish I could find my NHRA rule book.....if you look in the rules for the street classes there is a clause that if you have an UNMODIFIED car that can run those times from the factory a roll bar and harness is suggested but not required. And that if you modify the car in any way (Drag radials? I don't know

) then you must tech under the regular NHRA rules. My book is from 2004 so it may have changed but it was definately in there.