My dad and I installed a cage in my car in 2007 when we back halved it. We installed a Window Net at the time and I only ever used it ONCE. The 1st pass I made after we back halved it. The ran mid 11's than and run mid 10's now. I don't travel to many places, but have been to a handful of tracks over the years and no one has said a word about me not using it. Some tech guys can be a real PIA, but lately seems like tracks just want cars to show up. Some tech guys don't know the rules real well and the way things are written is not always clear English. I have been given grief before about having out dated seat belts in my car (It was slower than 11.49). So I printed out the part of the rule book that says they don't have to be updated to show them when they gave me a hard time,