The IS-F sedan is unlike any Lexus ever built because it's the first genuine high-performance model from this Japanese automaker, which tops luxury class rivals such as Mercedes-Benz and Cadillac with rather soft, high-quality vehicles.

The $56,000 IS-F is the most enjoyable model Lexus has ever built. It doesn't feel much like a Lexus and doesn't look much like one, either. Needed to accommodate a big V-8 are a high, wide hood, lengthened front overhang one must be careful not to damage in parking areas and swollen front fenders. Front fender vents don't contribute to the generally smooth styling, and the two double-decked exhaust outlets at each side of the rear end look a little over-the-top.

The rear-drive IS-F is the first in a new line of high-performance Lexus vehicles from that upscale Toyota division. Why the high-performance emphasis? Because rivals have youth-oriented high-performance divisions and the average Lexus buyer age is 61, with 70 percent of Lexus buyers being retirees. Long-term Lexus prospects thus don't look very promising unless it begins appealing to younger folks with cars such as the IS-F.

Cadillac found itself in a similar position several years ago and thus introduced its high-performance CTS sedans, which grabbed much younger customers and helped turn Caddy's "old-owner" image around.

The IS-F is loosely based on the Lexus IS premium compact car models, which have either 204 or 306 horsepower. But the IS-F shares little of its engine, transmission, suspension and chassis with the more pedestrian Lexus IS.

For instance, the IS-F has a ferocious 5-liter V-8 with 416 horsepower and gobs of neck-snapping torque. Remove its plastic cover and the engine looks like a wicked object from a "Terminator" movie.

The V-8 was developed with the help of Japan's Yamaha -- Toyota's longtime high-performance partner. Yamaha developed special cylinder heads with titanium intake valves for the IS-F direct-injected engine. In keeping with refined Lexus tradition, the IS-F V-8 isn't a high-rpm screamer like German rivals such as the BMW M3.

Toyota veteran Yukihiko Yaguchi, who originally suggested creating a high-performance Lexus division, was behind the IS-F project. He reportedly wanted a higher-rev (and possibly shorter-life) engine. But generally conservative Lexus vetoed that idea because it always has had its eye on 200,000-mile durability.

The regular two IS models have a six-speed automatic transmission, but the IS-F has no less than an eight-speed automatic that shifts deftly on its own -- or can be controlled by paddle shifters at the steering wheel.

The IS-F does 0-60 mph in an eye blink (4.2 seconds) and tops out at an electronically limited 170 mph. But with its performance and 3,780-pound weight, it's no fuel-miser, delivering an estimated 16 mpg in the city and 23 on highways. Premium fuel is needed.

The quick, precise electronic power steering puts the car exactly where you want it. The sport suspension has stiff springs and a thick anti-sway bar. It works with ultra-wide tires on huge 19-inch forged alloy wheels, which have an unattractive but race-oriented dark "smoke finish." Handling is sharp and high-speed stability is no problem. Vehicle stability and traction control systems and a Vehicle Integrated Management System with normal and sport modes are standard.

The ride is firm and generally comfortable, but the IS-F is so well-tied to roads that some uneven surfaces cause it to become jiggly. Huge brakes developed for the IS-F by the high-performance Brembo outfit provide short, sure stops, with electronic brake force distribution and a brake assist feature for panic stops. The pedal's linear action allows good brake modulation for smooth stops.

Four individual seats easily accommodate tall occupants. Front and rear seats are separated by a console. Front seats are very comfortable and hugely supportive. And unique blue LED illuminated needles for the speedometer and tachometer make them easy to read at a glance. Climate and audio controls are large, cupholders are sturdy and items such as as snap-out front door pockets provide decent cabin storage areas, although the glove compartment is small. Door handles are easily grabbed, but rear door openings are narrow.

The large, nicely shaped trunk has a low, wide opening for quick luggage removal action at airports.

The IS-F is first and foremost a Lexus, so it's loaded with virtually all the comfort, convenience and safety equipment you might imagine. Even the premium high-powered audio system has 13 speakers.

While not for your typical Lexus buyer, the IS-F is a solid first step on the Lexus journey to create a high-performance car line.