[Wiffles]

Hence why they should be made of carbon composites. They would still be a normal sized car, just made of carbon fiber. And carbon fiber is vastly stronger than steel, much lighter, and doesn't rust. Now for lean burn engines, you can basically tweak any car for a lean burn, but you risk burning off your valves, this is where ceramic components come into play. lean burn gives good efficiency compared to normal burn. ^^