Best Modern Seats?

I have installed BMW M3 Cab Seats with integrated 3-point seat belts. I made some sturdy brackets to attach the seats to the original bolt holes. I have also fitted angular steel rods underneeth the floor. But how do you guys strengthen the floor to accomodate for the momentum of a potential collision? If the seat tears the anchor bolts up through the floor pan, the 3-point seat belt seat actually reduces safety...

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