I've been covering cars for well over a decade, and never have I seen what I'm witnessing now: myriad new vehicles that are actually lighter and smaller (or at least no bigger) than the ones they've replaced. For as long as I can remember, next-gen cars have always been heavier and larger than their predecessors.Some of the corpulence can be attributed to such newfound goodies as airbags, side-impact beams, navigation units, and megawatt stereos, but most of it is due to America's idea that bigger is always better. This is why today's Jetta is the size of yesterday's Passat, and why the five-passenger Odyssey MPV has ballooned into the eight-passenger Odyssey B-U-S. Consumers may very well have wanted these bigger rigs, and automakers were more than willing to oblige them.

Not anymore. Sure, automakers are still out to satisfy the customer and make a buck-it is the car business, after all-but in many instances they're doing so without upsizing a new model. And, yes, even the gluttonous American consumer, in a time when volatile crude prices have pushed gas and diesel to around $4 per gallon nationally, is redefining "size matters." Small and light are in, especially for performance vehicles, and automakers are hopping onboard. Want proof?

Let's start with a gaudy example, the all-new Lamborghini Aventador. Never known for caressing a scale, Lamborghini's past supercars were always relatively heavy machines, a fact that didn't matter much because they housed the auto equivalent of a Pratt & Whitney turbofan behind the front seats. At around 3600 pounds, the Aventador weighs about 300 pounds less than the previous Murciélago SV. Jenny Craig isn't a Lamborghini spokesperson, but if she were, she'd tout the Aventador's feathery 325-pound carbon monocoque body cell, and point out that it isn't any taller and is actually slightly skinnier than the Murciélago.

Moving from the exotic to the everyday, there's Hyundai's Sonata 2.0T. Narrower and shorter in length than the previous boxy gen, the dashing current model measures lower in cabin volume but still is tops in its class. In addition to such weight savings as a 26-pound-lighter transmission with 62 fewer parts, the Sonata 2.0T uses a turbo four-cylinder in place of the old V-6, improving all aspects of performance-acceleration, handling, braking, fuel economy-thanks to less mass and more oomph.

And a vehicle's performance can even go up when power goes down. Take the new Subaru Impreza. A half-inch reduced in stature but no longer or wider, it tips the scales with about 160 fewer pounds, helping the 22-horse-weaker 2.0-liter seem as spunky as the outgoing 2.5.