Has anyone boxed in a cage area into the cabin? I tried to google but couldn’t come
up with much. Obviously not race legal. I did find one major Porsche company (you would all recognize the name but I’ve forgotten it for the time being) which did it to some of their special edition cars. I’m thinking sheet metal boxed area where a traditional cage would sit. Perimeter of roof, down A pillars. Then traditional cage structure from behind the driver, back. Stiffen the Chassis, possibly safe without full driving gear (slim profile and out of the way).
Edit: found the reference again. Ruf made them. I’ve never been in a Z with a cage, I suppose it is space dependant.
http://forums.pelicanparts.com/porsche-911-technical-forum/593488-ruf-integrated-roll-cage-irc.html