About weight, horsepower, mileage:
I bought an (original) Honda Insight a few years ago. It's basic construction is pretty high tech, aluminum and plastic with an astoundingly complex body. 1850lb including AC and the hybrid drive (~125lb incl battery, motor, and power electronics). It's fully modern in terms of crash protection, airbags, ...
3 cyl maybe 65 hp gas engine with ultra-lean (22:1) mix (under the right circumstances)
10 hp electric boost which mostly makes it more drivable since the engine is tuned for top end
weirdly-spaced 5 speed manual gearbox
0-60mph is maybe 10 or 11sec, not exactly sure, but it's surprisingly not bad
55mpg overall since I bought it, and I drive it like I stole it
A sales bomb for Honda, probably a lot of reasons, one being that Honda wanted a halo car, and couldn't make money on a car that cost $30k to build but only $20k to buy (guessing here but all that aluminum and fancy engineering doesn't come cheap). But mostly people just don't give a rat's ass about burning oil, which is shameful IMHO.
I think it would take another step in design (tandem rather then side-by-side seating, plug-in hybrid, ...) to get 80mpg without really sacrificing performance but it's a tragedy that as a society we're not doing those things.
It's also funny how much fun it is to drive compared to the Porsche. The difference is that I can actually drive the Insight at 90% of its limits on public roads (carefully) but to get the Porsche to that point is tricky and dangerous, if not outright reckless. I can toss the insight around turns (throw away the electric steering booster and it's got great feel), grab a gear for 4 or 5000 rpm and control the understeer as if I were driving a 60's mini cooper, half skidding on the skinny high efficiency tires. The Porsche is great but the Insight is just a gas. BTW, at the point that each of the cars lose traction in a turn the 968 (stock suspension) has way more body roll than the Insight, kind of funny.