A 5.9 was in consideration for some time. Hacking 3 inches out of the oil pan would make it fit.

Those cars you mentioned are smaller than the Imp but they do, indeed, float down the road. When it comes to a collision, I'm afraid the car would survive much better than the occupants. I tend to be wary of being T-boned in the Imp. That half height B pillar will lay down and I'd have the offending vehicle sitting in my lap.