All GT cars destined for everywhere except North American are factory provisioned for roll cages. You can either order strict from the factory or afterwards. The body in white is reinforced in the right places for roll cages.

North American cars do not have the reinforcement for roll cages, a decision made at the board level just so no one there can put a cage in their car and then have the cage failed and sue Porsche.

The simplest 'solution' is to fit a cage without reinforcement, just sort of jerry rig attachment points to the body, and in a roll over, the cage will simply punched right through the body, you might be killed are seriously injured, but the cage will be intact. 

Secondary solutions would be for 'tuners' to weld in reinforcement plates around the attachment points, but to date, none of these companies are willing to take the responsibility for the aftermath of a roll over. Their 'warranty' stopped at the point just before you are injured. 

One can blamed the lame 'unbelted occupancy' law in the DOT provision. At last count there is still 3 states in the USA that don't mandatory seatbelt for occupants. Hence 'factory' roll cages are required to be padded in the event that an unbelted occupant flew around inside the car and hit solid steel with their head. Some manufacturers, namely BMW, got around that rule by putting some Mickey Mouse foam padding on their cage. Porsche refused to do such a thing. Hence no cage for North American cars. 

This fact affects Canadian cars too, since we are under the same umbrella for 'North American' productions. Even when all of Canada required occupants to be belted. 


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