Horsepower is taking center stage for General Motors at the New York International Auto Show that opens today and runs through April 3.

Chevrolet is debuting SS versions of the 2006 Chevrolet Malibu, Malibu Maxx and TrailBlazer, while Cadillac is revealing a 440-horsepower, supercharged version of the XLR sports car.

The Malibu and Malibu Maxx, built at the Fairfax plant in Kansas City, Kan., are interesting vehicles for the SS treatment. They are distinguished from regular Malibus by flangeless, 18-inch wheels; unique front and rear fascias; a blacked-out crosshatch grille; projector beam fog lamps; rear spoiler; and dual chrome-tipped, 3.5-inch exhaust outlets.

The hatchback Maxx is 6 inches longer than the sedan and has a back seat with 7 inches of adjustment. The back doors are 4 inches wider than a regular Malibu, and there's a glass skylight over the back seat.

"SS has always stood for attainable performance - vehicles that deliver an exciting driving experience across a variety of products," said Brent Dewar, General Motors North America vice president of marketing and advertising. "From V-8 rear-drive vehicles to supercharged front-drivers, the scope of what makes an SS is broader than ever before, yet every vehicle wearing the SS badge signals performance and attitude with strong value."

The SS name was first used on a 1957 Corvette prototype that raced at Sebring, Fla. The legendary 1961 Impala SS, with a 409-cubic-inch, 360-horsepower V-8, was the first production car to carry the SS label.

The front-wheel-drive Malibu SS has a new 3.9-liter V-6 engine rated at 240 horsepower and 245 pound-feet of torque. This engine is a variant of GM's 60-degree, overhead-valve engine. It has an active air intake system to give the engine a flat torque curve for strong off-the-line acceleration. In fact, up to 90 percent of the engine's peak torque is available from 1,800 to 5,800 rpm.

An electronically controlled cam phaser controls the variable valve timing. This is GM's first cam-in-block engine to use variable valve timing to optimize torque and power over the broadest possible rpm range.

The transmission is a four-speed, Hydra-Matic automatic transmission with adaptive shift control to optimize shift patterns for varying driving conditions. The transmission has a manual-shift mode so the driver can choose to change gears as she desires.

More horsepower demands a firmer suspension, and the Malibu SS has front and rear springs tuned to complement specially valved shocks and struts. Front and rear stabilizer bars are larger to lessen lean in turns. Hydraulically assisted rack-and-pinion steering is used because it offers more precise steering.

The 18-inch wheels can be equipped with all-season or "summer only" tires. Summer tires have superior dry-road traction. Traction control and antilock four-wheel-disc brakes are standard.

Inside, the Malibu SS has a unique instrument cluster with chrome-ringed gauges, red needles and the SS logo. The cabin is decorated in black. Leather seats have cloth inserts and contrasting stitching. The steering wheel and shift lever are both covered in leather.

Convenience options include a sunroof, six-disc CD changer, OnStar and XM satellite radio.

The SS is available in white, black, blue and silver.

Production is scheduled to begin in the third quarter of this year. Pricing will be announced later.

Engine: 3.9-liter, 240-hp V-6

Transmission: automatic

Front-wheel drive

Wheelbase: 106.3 inches,

112.3 inches Maxx

Curb weight: 3,315 lbs.,

3,476 lbs. Maxx