Tube chassis/fiberglass deal that weighs 600-700 pounds less than my all-steel, all-glass, full unibody (back-halved) station wagon with power windows, power locks, keyless entry, full interior, full lights, turn signals.
Mine goes nearly as fast as his does at a much heavier weight...and it lives. I've had the same motor parts (crank, pistons, rods, head, block, sleeves, mains and even rod bearings in one of them) in it for 2.5 years without any breakage or failures.
I still haven't cranked it up yet...got another 10-15 pounds to go.