the least expansive super car?

ImportConvert

All those cars you posted pictures of, and the OP's first picture have some differences.

One, the OP's car uses square "tubing" in the door area.

Two, there are only 2 pieces of said square tubing with no cross-bracing by that door area.

If some dillweed is going to hit you, it will probably be the worst from the side. OP's picture of the "frame" just doesn't inspire confidence in me regarding size-impact.

The NASCAR looks bulletproof, and the GT3 as well, and is based on a frame of sorts. Huge X-bracing (tubular) by the doors. Like. The Zonda, well, your pictures didn't show this:
Those seats are sitting low and behind some serious frame protection from the sides. Again, very awesome.

All are much better than 2 pieces of squared steel "tubing" that have no crossbracing anywhere near the impact point that worries me most (driver/passenger door).

I am not denying that tube chassis are not the bomb if done right (not as a cost-saver like in OP's photo and what I was referring to), just that I would rather have a 6" hydroformed steel or aluminum chassis rather than a small square tube between me and a T-bone incident.

The car the OP posted and the Zonda, GT3, and NASCAR aren't even in the same league--and that was the point the OP was making. The car they posted was the least expensive "Supercar" to be had. The structure of it just doesn't inspire my confidence. Glad you all like it, though. I would rather have a perimeter frame car, or properly built tube chassis car like the others pictured.