The luxurious STS sedan is made to explore the wide-open spaces of New Mexico

These past few years have been golden for Cadillac, but there’s change in the wind. A product renaissance kicked off by the introduction of the CTS sedan has run its revolutionary course, as an evolutionary all-new model is preparing to land on dealer lots pretty soon.

Every model in the Cadillac range has been introduced or re-imagined during this time, from the well-regarded SRX crossover to the striking XLR roadster, from the traditional DTS sedan to the iconic Escalade.

And now it’s time for the luxurious STS, the sedan that stands above the CTS as Cadillac’s premier four-door. For 2008, there will be numerous improvements, from reworked exterior styling to a new base engine, the most powerful V-6 ever made by General Motors. But all that is a story for another day.

Here, we send off the current STS in style. One of the first things GM’s revered car czar, Bob Lutz, decreed upon taking the reins was a finesse of the STS’ styling before it hit the market. If the smaller CTS was all angles, he saw that the pricier STS should temper that obsession with a bit of romantic sweep. You see it in the roofline, as it glides back toward the trunk. It’s just a touch of grace, but is that enough to set the larger sedan apart?

End of the line?

Talk is cheap; so, therefore, are Internet rumors.

The future of Cadillac is still to be determined, the topic of much discussion. There was a push to create a range-topping supersedan, based on the sumptuous Sixteen showcar from a few years ago (and this year’s Albuquerque auto show), but that talk has cooled in the face of new fuel-economy rules on Congress’ agenda.

In Europe, Cadillac has just released its first wagon, a version of the BLS sedan, which is based on the Saab 9-3. Should a Cadillac be front-wheel drive when a keystone of the resurgent brand in the U.S. was a prescient switch to rear-wheel drive, a quality that puts Cadillac in the running against the German titans in the eyes of conquest buyers? The BLS isn’t expected here anytime soon, neither as a sedan nor a wagon. And that’s fine because our local dealer has both covered, selling Saabs and Cadillacs. No one needs the overlap.

But the cheap talk facing us today is the idea that Cadillac might drop the STS sedan as the sun sets on this generation after the turn of the decade. It’s true that the sporty CTS is perilously close in size and status: Its size lines up with the 5 Series BMW while its prices mirror the smaller 3, but the larger STS isn’t large enough, not competing head-on with the Germans’ top-level sedans in those two important quantifications, size and status. The STS, instead, is a half-step above the CTS, not the clearly delineated full step the Germans are so keen on.

It’s interesting to note that, for all the effort spent to re-energize Cadillac, the luxury brand hasn’t gotten everything. Like Buick, Cadillac has been growing in China, where buyers can now buy a longer-wheelbase STS, called SLS. That one would better align Cadillac’s range with the luxury players from the Continent. China also gets a different, nicer interior design. How much better an argument could Cadillac make for its biggest sedan with those key differences? It would make so much sense.

But does that make our STS less of a car? No.

The STS is a vitally important half-step in America. Cadillac is not yet ready for an all-out attack on the S-Classes of the world. In pricing, a top-level sedan would have been slighted because the recognition wasn’t there. In power, GM doesn’t have a readily available V-12 engine on the shelf to create the needed halo effect. But the STS lays the groundwork for an upscale push, if one is to come, and has faithfully held its spot in the Cadillac hierarchy as the car that says you’ve arrived at an important level, one just slightly higher than the driver of a CTS has attained.

Different enough?

The STS is a handsome car, tightly tailored to fit into the dashing Cadillac aesthetic without looking out of place next to the rest of the line. The large headlights and bold grille taper into the slightly softened greenhouse that speaks to a more refined crowd than the youthful, all-slashes CTS.

And just as the overall shape is softer, less brash, more restrained, the grille is wider and better integrated. Those headlights, so similar, feel less like they’ve been tacked on. The whole exterior style is less about the sum of the pieces and is more interested in the flow of the whole car.

Out back, there are fewer disparate parts; instead there’s a feeling of integration instead of the angry slashes of a child’s crayon that make up the CTS’ driving-away view. The differences are subtle, but the STS feels like it was designed more as a whole, that there’s more confidence in its style; the CTS was a shot across the bow of other upmarket automakers while the STS is an assured luxury sedan, ready to present its case instead of shoving its design down your throat.

Inside, it’s another half-step back up to the standard of the world. The dashboard, while a handsome attempt that helped pave the way for the resurgence of stunning GM interiors, hasn’t made it all the way — it’s a pastiche of small buttons, disparate surface treatments, varied dingbats meant to impart information and a slightly unintuitive clustering of controls.

And yet it’s a nicely restrained place to spend time: no iDrive knobs, no blinding slashes of chrome, no needless complication for the sake of “improvement.” Just don’t choose the test car’s tan interior finish: You’ll rightly like the idea for hot summers, but the top of the dashboard gets the same treatment, casting a thick glare on the windshield, affecting your view. When this color scheme is done with more care, the dash is black to shrink from your field of vision.

The seats are plush — wide and soft: They’ll work at holding you in place, should you hit a winding road. And those in the front row are both heated and cooled, an important feature all cars should offer. Plus, the steering wheel is heated: More than a silly indulgence, this is the kind of feature that sets luxury cars apart from run-of-the-mill appliances.

Space in the second row isn’t outstanding: This is not the limolike feel you’d expect in Cadillac’s top sedan. I’d even argue that it’s hard to tell the difference between the space offered back here in the CTS and STS. This is where that half-step decision becomes unresolved compromise.

Sipping down the miles

I drove the STS with the base 3.6-liter V-6, the engine that will be dropped in the next model. With a strong 254 horsepower at 6,500 rpm and 252 pound-feet of torque at 3,200 rpm, I struggle to see the need for the upgrade. The engine whips the STS up to freeway speeds just fine, humming quietly to itself as its does so.

Point the STS east and find U.S. 84 as it veers off Interstate 25 just before Las Vegas, as I did, and the car will simply sip down the miles. This flat road cuts through the Great Plains to meet up with Interstate 40, with windblown fields on either side stretching out to the horizon.

On a straight road, heading practically nowhere, the STS comes into its own. It’s silent in the cabin, the navigation system offering up a lonely pointer surrounded miles and miles of nothing. With XM satellite radio massaging the ears, I could drive the STS through all this emptiness for days without noticing. The ride is soft, there’s no noise to bring you up to the surface, the STS confidently flies over the open landscape. Point it toward the horizon, choose the second star to the right and just go.

The STS is available with all-wheel drive, both with its V-6 and V-8 engines. That’s an important distinction: The CTS only ever powered its rear wheels, though that changes with the new generation. Until then, that’s enough for me to prefer the STS: I’m a big fan of that extra level of traction, both when you’re carving mountain passes and trying to get home in a blizzard — or the freak deluge that hit as we took U.S. 285 back to Santa Fe — especially since technology has evolved to the point where any fuel-economy hit is small enough to chalk up to driving styles.

Driving the V-6 STS, I was never left wanting for more power, never had a problem with acceleration or back-road performance; then again, the engine never came off as particularly fun or exciting. Maybe it was the low mechanical whir: Being that this is a luxury sedan, that’s all I could ever hear — no noise from the exhaust or intake, no tires thrumming, no wind buffeting. Nothing to disturb the driver and passengers, but little passion either. Maybe that’s where the 320-hp V-8 model and the rip-roaring 469-hp supercharged STS-V come in.

Whether you need it or not, it only makes sense that a more powerful V-6 will be offered for 2008: The new CTS gets the base STS engine as its default offering, so the STS will get its uplevel engine, a high-tech, direct-injection V-6 — whipping up an impressive 304 hp and 273 lb-ft of torque — as base engine. See what happens when cars are stacked so close together?

What isn’t all jammed together is the pricing: The STS starts at $43,135; V-8 models range between $52,555 and $60,745 before you start adding separate options; the V is almost laughably presumptuous with its starting price of $77,855, though options are few.

Will the STS be let out to pasture at the end of this generation, having confidently taken up the torch and soldiered on as the envoy of the Cadillac line? Its lot in life was never easy, at times overshadowed by its precocious little brother. But it did its job, extending the brand up, blazing a path for the next range-topper, whatever that might be. We don’t know yet, but I salute the STS for being an unassuming luxury sedan that’s taken solace in the smaller pleasures of style, comfort and quietly superior power. Because isn’t that what luxury comes down to, after all?

Jay Binneweg is automotive editor at The New Mexican. E-mail him at drive@sfnewmexican.com.

2007 Cadillac STS

• Base price: $43,135
• As tested: $51,265
• Type: Front-engine, all-wheel-drive, five-passenger luxury sedan
• Drivetrain: 24-valve 3.6-liter V-6 producing 254 horsepower at 6,500 rpm and 252 pound-feet of torque at 3,200 rpm; five-speed automatic
• EPA mileage: 17 mpg city/25 highway, regular unleaded
• Length: 196.3 inches
• Wheelbase: 116.4 inches
• Weight: 4,166 pounds
• Built in: Lansing, Mich.