Used 2005 Cadillac STS

When Cadillac introduced its Evoq concept car over five years ago, it was a clear signal that it was no longer business as usual at GM's premier luxury brand. Fins and flabby rides were clearly out. In their place would be sleek, distinctive cars that delivered equal parts luxury and performance — or so the sales pitch went.

Since then, Cadillac has made good on the promise of the Evoq by introducing a string of new vehicles that not only wear similarly distinctive lines but deliver equally attention-getting performance. First, it was the in-your-face Escalade in 2002, followed up by the hard-edged CTS sedan a year later. The conversion continued with the SRX crossover and the XLR roadster (the production version of the Evoq) shortly thereafter. And now, in what Cadillac calls the final piece of the puzzle, comes the fully redesigned STS flagship, a sedan that may be a little late to the revival but no less important to its success.

In fact, after driving several preproduction versions of the STS, we think Cadillac may have been saving the best for last. Unlike the previous Seville STS that lacked the refinement, performance and aesthetic appeal necessary to compete against the best from Europe and Japan, the 2005 STS (the Seville name has been dropped) is a slick-looking, no-excuses package that gives up nothing to its competition.

Defining who that competition is exactly can be a little more difficult. Like the CTS, the slightly larger STS doesn't fit squarely into the well-defined size categories of the luxury class. It's slightly bigger than most midsize luxury sedans in both length and wheelbase, yet with a starting price of around $41,000, it's positioned to contend with a number of considerably smaller import competitors. With V6 or V8 power and available all-wheel drive, the STS can effectively compete with everything from a base model BMW 5 Series to a Mercedes-Benz E500 4Matic.

And we're not just talking price, either, as the STS delivers a level of performance that places it alongside the world's best without qualifications. Utilizing the same rear-wheel-drive Sigma platform as the CTS and SRX, the STS now has the setup required of a proper performance luxury sedan. It also boasts one of the stiffest frame structures in the industry, yet the car's mass was kept to a minimum through the careful use of lightweight components. With a curb weight of 3,921 pounds, a V8 STS is only about 100 pounds heavier than a comparably equipped 5 Series sedan despite its larger size. Add to that a nearly endless list of advanced chassis, suspension and drivetrain technologies, and you can begin to see why the STS is now the best car in Cadillac's lineup.

The lack of overbearing weight gives the STS a far more nimble feel than its dimensions might suggest. It's not exactly sport sedan-quick in its movements, but with only moderate body roll in corners and minimal dive under braking the STS can be pushed hard without losing its composure. With the rear wheels providing the power, Cadillac's engineers were free to focus on the kind of precise steering feel that's nearly impossible to achieve with front-wheel drive. The result is a delicate feel through the steering wheel without a numb on-center sensation or overly aggressive assistance. It's not perfect just yet, but combined with the solid chassis, it's one of Cadillac's best setups to date.

The Magnetic Ride control (MR) system that was first introduced on the previous-generation STS remains an option for those who desire some adjustability in the vehicle's ride quality. With two different settings to choose from, it can be tailored for either day-to-day comfort or back-road performance. We found either setting capable of handling most situations, but the sport mode does sharpen things up a bit. For the dedicated enthusiast, there's also a new sport package offered that serves up variable-ratio steering, heavy-duty brake linings and high-performance 18-inch Michelin Pilot Sport rubber.

As impressive as the STS is when it comes to ride and handling, the aspect of the car that impressed us the most was the drivetrain. Whether it was the surprising power of the base V6 or the smooth delivery of the Northstar V8, we found little to complain about under the hood. Both power plants use advanced overhead cam designs and variable valve timing to deliver broad power bands and refined operation.

With 255 horsepower and 252 pound-feet of torque, the standard 3.6-liter, six-cylinder engine is able to get the big sedan up to speed with surprising gusto. Unlike some of its competitors whose six-cylinder offerings provide merely adequate performance, the V6 in the STS rarely feels underpowered. It doesn't snap off the line like the bigger V8, but with solid midrange torque and a willingness to push hard to the redline, it's more entertaining than you might expect.

Step up to the 4.6-liter V8 and the STS really shows its mettle. With 320 hp and 315 lb-ft of torque, there's more than enough power to make this car feel quick. Cadillac claims a 0-to-60-mph time of less than six seconds and it feels that fast behind the wheel. Some of the credit has to go to the standard five-speed automatic transmission, as it serves up perfectly executed shifts no matter how hard the pedal is pressed. Eight-cylinder models also offer the option of all-wheel drive for those who live in harsher climates. The added weight of the extra hardware slows things down a bit, but you would be hard-pressed to detect the system's presence during everyday driving. It's yet another sign of just how well the drivetrain components work together to help push the STS up another notch when it comes to overall performance and refinement.

Much the same could be said about the interior of the STS. This is an area where Cadillac has never put its best foot forward, but the STS shows signs that progress is finally being made. Panel fitment was generally good and the underlying structure seemed solid even in our preproduction test cars. The wood trim is richer-looking than before, and the seat materials feel a grade higher. Given that a few of the interior pieces weren't quite production quality, we'll reserve our final judgment for now, but our initial impressions were of a cabin that looks and feels as it should in a sedan of this class.

Beyond the more simplistic renovations, the STS also incorporates a vast array of high-tech features buried within its spacious cabin. A push of the remote button can not only start the car from up to 200 feet away, it can also activate the climate control system to heat or cool the vehicle depending on the outside temperature. Once inside, the driver can get information through a four-color head-up display projected onto the windshield while every occupant can enjoy the sounds of an optional 15-speaker Bose 5.1 surround sound audio system. Other options include a DVD-based navigation system with an eight-inch color screen, Bluetooth wireless cell phone connectivity and an Intellibeam headlight system that automatically switches between high and low beams according to oncoming traffic.

Needless to say, the STS has been designed to go heads up with the most technologically advanced vehicles in the world. Better yet, it is also endowed with the more fundamental requirements of a true luxury car like a sturdy chassis, precise steering and the latest drivetrain technology. Throw in the fact that it wears Cadillac's design language better than any other car in the lineup, and the STS rightfully deserves its place as Cadillac's flagship sedan. It may not be as nimble as the CTS or as flashy as an XLR, but for buyers looking for a complete package of luxury and performance, the STS is Cadillac's best offering yet.