The problem is that when a car starts out with a Darth Vader face, what follows it better be able to swing a pretty good lightsaber. And the density of visual misanthropy that follows in this case rapidly dwindles until, by the car's stern, it's as innocent-looking as a Camry. Dynamically, the F Sport -- a package of primarily handling and appearance enhancements -- is a lot more consistent, however.

While the fright mask suggests it's looking to quarrel with a BMW M5, its appropriate eye-to-eye opponent would be the duller-fanged, 300-hp 535i. The GS's upgraded 303-hp engine and paddle-shift six-speed transmission are carried into the F Sport largely unaltered, providing 0-60-mph dashes in 5.5 seconds and delivering 19 city mpg and 28 highway (the latter number is up from 26 mpg).

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Five-point-five seconds is brisk. But not sizzling. Trust me, though, that this is one of those rev-oriented mills that makes a much better impression on the road than at the dragstrip, despite the absence of a de rigueur seventh gear cog. However, where the GS 350 F Sport really, really clicks is when the asphalt bends. Turn-in is very precise (thank you, rear steer), its stance is firm (particularly in the 'Sport+' suspension setting, though its ride is a bit shaky on the straights), and there's a nice little drift available if you press matters exiting the corner.

Active rear-steering is a rare technological bird, and like its sporadically appearing predecessors, this vehicle aims its rear wheels oppositely than its fronts at lower speeds (here, 50 mph) for sharper cornering, while slightly mirroring the front wheels at higher speeds for increased stability. Lexus says the rear's maximum angle is 2 degrees; we say it's a well-implemented solution, offering noticeable agility without the handling fishiness these things can sometimes invoke. Yet, even without the system (it's an F Sport option), the GS' handling game has clearly been elevated. Both the front and rear tracks have been broadened by about 2 inches; the rear suspension is an all-new multilink affair; larger bushings are employed up front; and the entire suspension is aluminum, lowering unsprung weight. The F Sport package takes this goodness even further with fatter anti-roll bars, stiffer springs, variable-ratio steering, bigger brakes clamped by more aggressive pads, and staggered 19-inch tire sizes - 235/40s up front and 265/35s in back. There's also that variable damping (Sport+ being its apex of aggression), which locks down the car's body motions, though the jiggly ride that ensues is enough to reserve the switch for sporadic amusement only. Sport+ also dials up the throttle's response, but that's completely overwhelmed by its teeth-gritting chassis dynamics. (Have I mentioned the ride enough?)

Other GS 350 pleasantries include its thin, vision-enhancing A-pillars, its rich interior surfaces (ours was detailed with brush aluminum), and a giant, high-resolution 12.3-inch display screen. Because of the screen's extraordinary width, there's enough real estate to show multiple things at once. It typically displays a navigation map on a large portion, and either sound system or climate control info on a smaller one. It's awfully nice not having to flip between screens as is necessary with smaller, conventionally sized units, and its resolution is absolutely crystalline. Beautiful, in fact. Mark my words, in-dash car displays are heading the way of America's living room TVs -- they're going BIG SIZE and HI RES. Another gold star goes to the very supportive seats, which provide a mesmerizing 12 means of adjustment (heavens, a Porsche GT3's seatback can't be raked at all).

Is there a dark side, Luke? No. But maybe some shades of grey. While the F Sport's variable-rate steering enables X-Acto-knife handling sharpness, its light-effort weighting seems mismatched with the F Sport's seriousness and scale. Beefy, menacing car; light, delicate steering. It's like Claude Van Damme with Truman Capote's voice.

Climb into the backseat and you'll find plenty of headroom. Nevertheless, your knees wind up high and your butt low, and worse, the GS' tall, rear-wheel-drive center hump effectively renders it a four-seater, unless your fifth passenger is Yoda-sized. And although the trunk space theoretically has been expanded by 25 percent to a promising 14.3 cubic feet, don't image it as some simple, rectangular cavity. It's badly violated by that wonderful rear suspension, and most effectively filled with lots of smaller suitcases.

But let's walk back to the front end of in car. Behind the grille of the GS 350 F Sport -- after you remove the scary Darth Vader mask -- is a reality its wearer would prefer not to reveal. Darth Vader was Luke Skywalker's father. This F Sport is a large Lexus sedan claiming to burn up backroads like a 5 Series BMW. It does a remarkably good job of it. But it also asks buyers who are naturally in the BMW camp to write a Lexus check. That may not be so easy.