DETROIT – Toyota Motor Corp.’s Lexus luxury division has been tearing up the lower-luxury segment in the U.S., and now the auto maker is planning a new product expected to continue the onslaught.

In 2006, Lexus sold 60,597 units of the all-new ES sedan and 54,267 units of the new IS 250/350 sport sedans in the U.S., according to Ward’s data.

The IS, which was redesigned for the ’06 model year, picked up significant momentum, finishing the calendar year in fifth place behind the BMW 3-Series, Acura TL, Infiniti G35 and ES 350. It outsold the Cadillac CTS (which is completely redesigned for ’08), Mercedes C-Class and Audi A4 in 2006, Ward’s data shows.

Lexus takes a unique approach to the segment, offering the ES for luxury-oriented customers and the IS for enthusiast drivers.

Soon, U.S. buyers will see yet another Lexus marque in the segment, one that takes the IS to extreme performance levels.

Lexus unveils the IS-F sedan at the North American International Auto Show, sporting a 5L DOHC V-8 expected to produce more than 400 hp and 350 lb.-ft. (474 Nm) of torque.

The 5L has specially engineered cylinder heads fed by a 2-stage intake manifold and dual fuel-injection systems (for both direct and indirect fuel injection).

The mill shares its block and architecture with the 4.6L DOHC V-8 in the upcoming Lexus LS 600h L hybrid-electric vehicle, Bob Carter, Lexus Group vice president and general manager, says.

But the IS-F’s larger 5L V-8 is tuned specifically for aggressive driving in a smaller, lighter vehicle. Carter says the new IS-F meets the three goals set for the program: “It must be balanced; it must be authentic; and it must haul ass,” he tells the crowd, describing the car as a “fire-breather.”

But the F in the nameplate does not stand for fire. Instead, it signifies flagship and harkens back to the initial Lexus brand when it was created 20 years ago, internally coded “Circle-F.”

Competitive vehicles for the IS-F include the BMW M3, Audi RS4 and Cadillac CTS-V. A manual transmission is available in those vehicles but will not be offered in the IS-F, Carter says.

Instead, the 5L V-8 in the IS-F will be mated to an 8-speed automatic transmission with “direct sport-shift” sequential shifting actuated by paddles on the steering wheel. Lexus calls the 8-speed sequential-shift automatic the first of its kind in the world.

Carter says he is confident the car will register 0 to 60 mph (97 km/h) times in less than 4.9 seconds.

Consumer research of the segment has found manual transmissions are less important to buyers than many industry observers think, Carter says.

“What we are seeing is a trend in this enthusiast market – a convergence of both automatics and manuals,” he says, referring to torque-converter automatics with sequential-shift functions and Volkswagen AG’s Direct Shift Gearbox (DSG), an automated manual transmission without a clutch pedal.

He calls the IS-F’s 8-speed “a very good solution” for effectively transmitting the massive torque produced by the new V-8.

The IS-F arrives at Lexus dealerships in early 2008. Carter declines to project potential sales volumes for the vehicle. “But it will be a significant mix of our total IS volume,” he says.

Whether Lexus intends to create “F” variants of other vehicles, such as the GS sedan or RX cross/utility vehicle, remains to be seen.

“We have that under study at this point, what our next car will be,” Carter tells journalists. “Our first concentration is on the sport sedan series, and then perhaps later we could look at the SUVs.”

Carter also would like to see a production version of a concept unveiled Monday, the LF-A supercar equipped with a V-10 of unspecified displacement (with front mid-engine placement) targeted to produce more than 500 hp.

Lexus debuted its first LF-A concept at the Detroit auto show in 2005, but this latest iteration is closer to production ready, Carter says.

He declines to say whether the LF-A has a manual or automatic transmission, or how serious Lexus is about building the LF-A.

“We’re gauging consumer interest, but we had very good reception to the first-generation LF-A,” he says. “And this car represents much closer the car we would actually bring to market.”