I think the way we will all be driving these types of cars, the cage like the Spec Atom should be the lightest cage we should think about. Something about being upside down sliding along at 60 mph makes me worried about anything less. 30 or 40 extra pounds for thicker wall tubing or a few extra feet of it might pay back huge returns one evening. The 818 frame is no where near strong enough for my feelings. And the stock Atom with the center hoop only is asking for one shoulder to be ground off upside down.