CALABASSAS, CA – That collective exhale you hear is 945 U.S. Cadillac dealers breathing a sigh of relief.

The Cadillac XTS, a roomy, high-tech luxury sedan that pushes all the right buttons, arrives this month as a desperately awaited addition to the brand’s sparsely populated showroom.

Yet, as perfectly competent as the XTS proves itself during testing here, the car, alone, will not usher the General Motors luxury division into the second phase of its renaissance.

That’s more the job of the volume-oriented ATS, a small performance sport sedan arriving later this summer and intended to tweak the ears of the class-leading BMW 3-Series, Mercedes-Benz C-Class and Infiniti G.

The XTS, on the other hand, fills a void in Cadillac showrooms as the classically proportioned large sedan missing from the brand’s portfolio since the STS and DTS wound down production last year.

If the throng of old-school Cadillac dealers fawning over the XTS at this year’s Detroit auto show wasn’t enough evidence, recent sales results bear more proof of how important a stretched saloon is to the brand.

According to WardsAuto data, Cadillac surged out of the recession in 2010 with sales rising 37%. But after STS and DTS production stopped last April and May of 2011, respectively, the brand eked out just a 4% year-over-year annual gain against an industry up 10.2%.

This year, sales are down 22.3% compared with an industry ahead of year-ago by 13.4%. Cadillac deliveries were off 21.6% in May, clearly reflecting the absence of some 2,000 monthly STS and DTS sales.

The DTS perennially commanded a share of WardsAuto’s Middle Luxury segment, surpassed only by the BMW 5-Series and Mercedes-Benz E-Class in recent years.

So here comes the XTS, galloping to the rescue, outfitted with GM’s venerable 3.6L gasoline direct-injection V-6 making 304 hp. A Ward’s 10 Best Engines winner in 2008 and 2009, the mill steadily has become the workhorse V-6 for GM by balancing performance and fuel efficiency.

The engine provides ample acceleration and passing power for a sedan tipping the scales at slightly more than 4,000 lbs. (1,740 kg).

We average 16.7 mpg (14.1 L/100 km) in an all-wheel-drive, top-of-the-range Platinum model. Not bad, given the miles are logged in a mix of stop-and-go traffic and an enthusiastic run through nearby canyon roads.

A 6-speed automatic transmission mates so smoothly, it’s easy to imagine a generation of dads behind the wheel, one arm stretched over the seat back and the other laid lazily over the tiller.

This Cadillac, however, is no land yacht. Sure, there’s the copious front- and rear-legroom any fullsize luxury sedan should deliver, as well as a trunk seemingly spacious enough to swallow up the Hollywood billboard perched over the city here.

But GM couples the excellent powertrain with an available Haldex AWD system, standard Magnetic Ride Control real-time suspension damping and, on front-wheel-drive models, HiPer Strut front-suspension technology to mitigate torque steer.

Picking our way along Sunset Boulevard in Beverly Hills, the XTS feels light and much smaller than its dimensions would suggest. And in the canyons overlooking Malibu, we get the same impression as the car weaves athletically up and down the narrow, curvy roadways.

An old-fashion hydraulic steering system with solid, on-center feel tops off its excellent, big-sedan driving dynamics.

The folks at Cadillac argue the XTS is no replacement for the DTS or STS. We’ve heard that line before, but in this case it’s true. Mechanically, the XTS stands on its own like no large Cadillac before it.

The same goes for the interior, where GM blends Cadillac’s unique style with refreshingly sensible technology in its most thorough cabin redo since the current-generation CTS bowed in 2008.

Micro-fiber suede blankets the headliner and A-pillar of our $59,000 tester, while buttery, premium-grade leather seats wrap front and rear passengers.

However, the attention to detail makes the greatest impression.

For example, a leather-trim insert adorns each side of the center console for extra knee comfort for front-seat occupants. An extra bit of seat bottom offers additional thigh support for long cruises.

Trim pieces lack unsightly breaks, including one narrow, titanium-like strip on the passenger-side dashboard. GM sprung for special tooling to make sure the piece stretched uninterrupted from the door panel, over the glove box, to the bottom of the center console.

There’s no ugly, oversized glove-box latch, either. Cadillac finally gets an inconspicuous push-button mechanism, although the face of the glove box should fit more snugly.

The star of the interior is the Cadillac User Experience infotainment system, which debuts on the XTS. CUE comes standard on all models and incorporates key vehicle controls such as audio, HVAC and a 3-dimensional navigation system rivaling industry-leader Audi for its vivid and detailed display.

We like the simplicity of the system, which adopts the functionality of an iPad to put its ease-of-use factor miles ahead of some competitive systems.

Touch an “app-like” icon on the clutter-free, 8-in. (20-cm) display screen, and all the controls for that particular piece of information or entertainment comes on a single page. Haptic feedback lets the user know the command was received.

The system responds to touches and swipes like an iPad would, and natural-voice recognition software frees users from memorizing specific commands. Proximity sensors anticipate the user returning to the screen after a break and reopens the appropriate page before your finger hits the screen.

Look for CUE in the ATS, too, and in the refreshed SRX cross/utility vehicle in the fall.

The XTS cuts a nice profile. It takes the brand’s Art & Science design philosophy forward, blending classic Cadillac cues such as the C-pillar’s sail panel with sharply creased sheet metal resembling a freshly laundered dress shirt.

The character line above the belt line and the chrome-accent rocker panel are particularly fetching. Handsomely shaped metallic trim connects the exterior mirrors to the base of the A-pillars, repeating the rocker-panel treatment. The mirrors also house a slender light bar for the turn signals.

The front panels borrow some cues from the Buick LaCrosse, but on the whole GM differentiates it well from its platform sibling. Green-minded buyers will like the capless fuel filler.

Our Platinum tester comes with 20-in. aluminum wheels, wrapped in Bridgestone rubber and polished to a high shine. GM fits chrome accents into the wheels, which simultaneously punch up the brightness factor and can be swapped out for less-expensive wheel packages.

The grille treatments between Platinum models and the rest of the range differ slightly, although it takes a close eye. Unfortunately, the gap between the hood and grille stands out most, a victim, GM says, of the need to design against over-slam.

The XTS ushers to market new safety technologies for GM, including a standard “Driver Awareness” package with lane-departure warning, forward collision alert, side blind-zone alert, rear cross-traffic alert and a driver’s seat that pulsates to warn drivers from which direction those dangers might be coming.

An optional “Driver Assist” package adds adaptive cruise control, front- and rear-automatic braking and automatic collision preparation.

The XTS is smaller than but competes with the Mercedes-Benz S-Class, Lexus LS and BMW 7-Series. Dimensionally, the XTS is more closely aligned with the Audi A8. The XTS probably would have a better shot at winning over those buyers, as well as our unqualified endorsement of the car, if it were rear-wheel-drive.

But that’s not what buyers of this particular Cadillac desire, so look for a range-topping, longitudinally oriented Cadillac sometime down the road. For now, the XTS fills the big Caddy bill quite nicely.

’13 Cadillac XTS
  Front-engine, all-wheel drive, 5-passenger sedan
Engine 3.6L gasoline direct-injection V-6 with aluminum block and heads
Power (SAE net) 304 hp @ 6,800 rpm
Torque 264 lb.-ft. (355 Nm) @ 5,200 rpm
Bore x stroke (mm) 93.9 x 85.6
Compression ratio 11.5:1
Transmission 6-speed automatic
Wheelbase 111.7 ins. (284 cm)
Overall length 202 ins. (513 cm)
Overall width 72.9 ins. (185 cm)
Overall height 59.4 ins. (151 cm)
Curb weight 4,215 lbs. (1,912 kg)
Base price $44,995
Fuel economy 17/27 mpg (13.8-8.7 L/100 km)
Competition Audi A8, BMW 7-Series, Lexus LS, Mercedes-Benz S-Class
Pros Cons
Unique Cadillac styling Build-quality hiccup
Attention to detail Bit gap-toothed
Excellent big-car handling Left pining for RWD