I think there is some confusion here......
Niterider, you have a bolt-in or welded cage, correct?
This thread is specifically for guys that would like to use the Schroth Quick Fit system
which allows you to have a 4-point belt system WITHOUT a cage (of any kind)....
This is obviously mostly to keep the driver harnessed and stable during cornering and braking and I doubt adds or removes any safety attributes already built in to the car.