Cadillac wants to play with the big boys -- i.e. Mercedes-Benz, Lexus, Infiniti and BMW and Audi.

So don't call this new sedan a Seville, even though it carries the same alphabetic nomenclature as the midsize sedan once known as the Seville Touring Sedan.

Nope, this is the new STS, based on the exclusive-to-Cadillac Sigma rear-wheel-drive platform shared with the CTS sedan and SRX sports utility vehicle. And it appears to have the right stuff to play with its its midsize luxury performance competition -- BMW 5 Series, Mercedes Benz E-Class, Lexus GS430, Audi A6 and Jaguar S-Type.

The new exterior is a slightly softened version of the edgy Cadillac CTS design, a look first revealed in the 2001 Cadillac Evoq concept that turned into the Cadillac XLR roadster. Closer examination shows the STS rounds out the edges a bit, its classic Cadillac grille thrusting past less angular vertically stacked headlights, each element set in a chrome housing.

The car has a wide stance and characterful bumper with neatly integrated turn signals stacked over fog lights flanking a steel mesh lower air intake. There is no side trim, just subtle character lines, one running from the headlights to just below the chrome-trimmed window beltline until it merges with the vertically stacked taillights, the other from the front wheel wells up to the rear lights. The door sill has a slight indent above it to reduce the flat side shape.

The taillights are less blade-like than on the CTS and XLR, while twin exhaust pipes stick out under a pewter-gray rear valance. The STS rides on seven-spoke polished alloy wheels and Michelin P235/50R17-inch radials. The whole look is taut and different from the rounded Sevilles of yesteryear, the car better planted on the ground, less bulbous and more athletic. And fit and finish was very good, panel lines all straight and slim, the paint well done.

The interior echoes the more angular look of the CTS, with a touch of German somberness as well. The front seats are 10-way power adjustable with air conditioning as well as heating, plus height-adjustable power lumbar support. They were comfortable and easy to set up, but didn't offer a lot of side support for the younger buyer Cadillac hopes to lure into this car. The three-spoke wood and leather-clad steering wheel has a grippable rim with integrated stereo and voice recognition buttons, and power tilt and telescope adjustment. The electroluminescent gauge package offers a bright, concise 160-mph speedometer overlapping an 8,000-rpm tach with gas and temperature gauges and a digital trip computer/tire pressure monitor/engine monitoring display underneath.

The dash is covered in a padded, low-gloss leather-finish plastic. Slim air vents flank an 8-inch digital satellite navigation touch screen with main function buttons underneath, framed in warm eucalyptus wood. The climate control offers dual-zone temperature control. Two cup holders hide under a sliding door, and a padded center armrest hides a usable storage area. Overhead, one-touch power moonroof, HomeLink garage door and map light buttons are in a cloth headliner that didn't look as good as in German cars.

No key is needed to get into this kingdom or fire it up -- a remote start system allows you to start the engine via the key fob. Tap the key fob's unlock button, tap the brake, press a button and the rest of the car turns on while the key goes in your pocket -- cool! But a few times, the car wouldn't remote start. And I couldn't get anything to turn on from the driver's seat one hot afternoon, a problem since there is no ignition key slot. It eventually freed up, and never troubled me again.

Another piece of technology was cool and frustrating at the same time, and part of the satellite navigation system. Its touch-screen controls the superb 15-speaker Bose surround sound system (AM/FM/XM Satellite Radio/six-disc CD, and DVD movies when the car is parked) with speakers atop the front seats. Its different screens also alloy the driver to navigate, set alarm and remote lock functions, seat position memory, Bluetooth hands-free cellular telephone system, even set the suspension on "Touring" or "Sport."

You can change stations or switch audio sources off the steering wheel -- much easier than some German cars I know. Or ... tap a steering wheel button and you can ask the car to change the climate control, even open and close the windows, prompting our son to call it "wicked!" It can be programmed for multiple languages, from German to a butler-like male British voice or teacher-like female English voice. But despite my best attempts to speak clearly, proper commands like "system temperature 60" became "system temperature 68," while others like "System on" shut the a/c off.

The satellite navigation screen had glare despite up/down adjustment. And when I lowered the right rear window after it didn't budge under voice command, it stuck open, requiring a dealer visit for a new regulator. So much for technology!

Rear seat room was OK, with a rear a/c vent and controls, center arm rest with cup holders and a ski pass-through to the trunk. But it was a bit tight in leg room for two adults, while the trunk was just big enough, with a cargo net and a narrow opening.

On the road, the new STS tries very hard to feel like a German sports sedan with American comfort engineered in, and is light years ahead of the Seville Touring Sedan of a few year's back. Our test car's 320-hp Northstar V-8 with five-speed automatic transmission that can be shifted or set in "Sport" mode got to 60 mph in a fleet 6.4 seconds with smooth shifts and a subtle engine growl -- a half-second faster than the front-wheel-drive 300-hp STS we tested in 1998.

Magnetic Ride Control -- magnetic particles suspended in the suspension system react within milliseconds to road imperfections -- coupled with a suspension tuned on Germany's infamous Nurburgring race track offered a supple-yet-firm ride that smothered bumps and limited body lean in turns. Set on "Sport," the car was nicely tied-down in turns with no sloppiness, the steering direct but with a slight dead spot at center. The rear end stays planted in turns, even under power thanks to traction control. Shut off the traction control, and the StabiliTrak system waits in the background, offering some power oversteer before it comes in gently. The BMW 530i we tested was sharper in steering and turning response. But the Cadillac was a lot of fun to drive and well-controlled. Perhaps an STS-V version will give us a six speed manual and a bit less electronic nannying. The disc brakes offered superb control, good stopping power and no fade even after a number of hard stops.

The base price of our 2005 Cadillac STS sedan with V-8 is ,800, including standard automatic rear leveling suspension, traction control, Stabilitrak, cruise control, remote start, leather seats, power windows/door locks/mirrors, front and side air bags, rear parking assist, alarm and auto-dim rear-view mirror. Our test car added an ,065 luxury performance package with power front lumbar, heated/cooled front seats and heated rear seats, eucalyptus wood trim, Bose 5.1 Studio Surround stereo with in-dash six-disc CD/DVD changer, satellite navigation, XM Satellite radio, Magnetic Ride Control, rain-sensing wipers and HomeLink garage door transmitter. Manufacturer's suggested retail price -- ,560. For comparison, ,145 pays for a nicely optioned BMW 530i with 225 hp in-line six, and about ,000 buys a Mercedes-Benz E500 with 302-hp V-8.

Bottom line -- the new Cadillac STS has a serious dose of German fit and finish as well as handling and power, in a distinctive American body. The ride and handling, plus quiet interior are above-average for an American sedan, and so is the level of sophistication. It's too bad our test car had the ignition and power window problems, and the rear seat leg room is less than the long wheelbase indicates.