[A Cobra guy]

Life happens. My aunt ran over a rotory lawn mower blade that found it's way onto a freeway. It came right up through the steel floor of her Saab. Luckily no one was in the passenger seat and it missed the fuel and brake lines. My point is: a freak accident like that could happen in any car. Build a car you are resonably confident in and enjoy it. If I worried about all the safety features my E-M DOESN'T have I'd never pull out of the garage. Knowing how vulnerable I am in the car makes me a better driver.

Oh, and if floor board penitration is your particular fear, then most any of these cars could have 1/4 inch steel plate fitted down there.

I'm not making light of your question. Safety should be a major factor in selecting a kit vendor. A few take the topic seriously. But no kit will come close to a modern production car for safety.