Rule of thumb has always been if you have a cage (any type) you need a window net. Even though a car may not require a cage, if it has one they will require you have a net no matter what the rule book says, in my experience anyway. Not a myth just what I've told by Tech officials at local tracks.
I had a similar experiance several years ago. The car only ran in the 12's.I bought a used bolt in rollbar. The guy kept the swing out side bar since that plate was welded to his floor. When I got dinged in tech without the side bar, I complained that a roll bar wasn't required at all at 12 seconds. He said " put it all in, or take it all out". I got a side bar before the next race.
