Reply #29: I remember the ESX-3. It was all plastic.

[Xithras]

I think I still have an old copy of Popular Mechanics out in the garage with an article on it. I recall that there was a bit of buzz at the time about whether people would buy an all-plastic car (the ESX-3 had a light aluminum frame to make the plastic rigid, but that's it). Even more importantly, would people buy an all-plastic car that would have been street priced at around $10k more than its less efficient competitors. The consensus ended up being that they wouldn't, and the project was scrapped.

On edit:

I searched PM's website and found the article on the ESX-3: http://www.popularmechanics.com/automotive/motorsports/1268751.html?page=2 It was a 3 cyl diesel hybrid linked to a paltry 20HP electric motor.