Development of the new 2013 Cadillac ATS was considered such a priority, it was one of the few programs that was not stopped during GM's bankruptcy. Why? Because the ATS is GM's entree into the largest luxury vehicle segment in the world, a segment basically created by BMW's 3 Series. This is the car that will make Cadillac a global luxury brand.

The new ATS faithfully follows the segment-defining BMW's formula. In fact, chief engineer Dave Masch would probably argue his baby Caddy follows it even more faithfully than BMW. The dynamic benchmark for the ATS was the E46 3 Series, the car many enthusiasts still regard as best of the breed. Masch's team believes BMW moved away from the driver-focused chassis tune of the E46 with the current 3 Series -- the E90 -- and expects that trend will continue with the next-gen 3 Series due later this year. They see an opportunity for Cadillac.

The ATS is virtually all-new from the tires up. About the only parts that could be considered carryover are the revised 3.6-liter DI V-6 and the 6L45E six-speed automatic transmission. It rolls on GM's new lightweight Alpha architecture - the base ATS weighs just over 3300 pounds -- and the chassis has been tuned to deliver razor-sharp steering, precise handling, and buttoned-down ride. The car has been optimized around 17- and 18-inch wheels to keep weight down and improve agility.

The first pre-production cars rolled down the line at the Lansing Grand River Assembly plant in Michigan just before Christmas. The ATS will launch as a sedan only, but coupe, convertible and wagon versions will be rolled out over the next two to three years. There will also be V-series versions. No official word on powertrain for the ATS-V, but a twin-turbo version of the 3.6-liter V-6 looks likely, partly because of the tight underhood packaging, but also because rivals like BMW's next-gen M3 are moving to smaller forced induction powerplants.

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THE ATS IN DETAIL

Engines

First application of GM's new Gen II Ecotec four-cylinder engine in a Cadillac. The engine features dual overhead cams, four valves per cylinder, and variable valve timing. It will be used in a wide variety of GM products, but the versions fitted to the ATS will be the most powerful.

Base engine is the 200-hp Gen II Ecotec 2.5-liter DI four, which made its debut in the new Chevy Malibu. The engine will power the base RWD car with FE2 suspension.

A 2.0-liter turbo Gen II Ecotec with 270 hp will make its debut in the ATS. This engine has the broadest bandwidth and will be used in RWD and AWD auto, RWD manual models, and with FE2 and FE3 suspensions.

Carryover 3.6-liter DI V-6 is revised for improved refinement and is rated at 318 hp in this application.

Transmissions

GM's 6L45E six-speed auto is standard transmission, and gets magnesium paddle shifters with FE3 suspension. Eight-speed autos are in the plan, but GM was forced to delay development during the bankruptcy.

An all-new Tremec six-speed manual will be available with the Turbo. Designed specifically for GM, it has a magnesium casing for weight reduction.

Suspension

Front: MacPherson struts with aluminum control arms connected to an aluminum subframe.

Rear: Five-link independent, light-gauge steel control arms, mounted to light-gauge hydroformed steel subframe.

FE2 suspension has standard 17-inch wheels and all-season tires. FE2 Sport Pack gets 18-inch wheels with all-season tires and Brembo brakes.

FE3 suspension has standard 18-inch wheels, summer tires, and Brembo brakes, plus next-gen MR dampers with Touring and Sport mode settings. Tires are different widths front and rear -- 225/245 -- and the ultra-firm Sport suspension setting was optimized on the Nurburgring.

Chassis

With overall length of 182.8 inches and wheelbase of 109.3 inches, the ATS is 8 inches shorter overall than CTS, but the wheelbase is only 4 inches less.

Front to rear weight distribution is 50/50 in turbo manual; 51/49 in other models apart from AWD, in which it's 52/48.

Limited slip diff is standard in FE3-equipped cars.

New ZF electric power steering offers variable assistance. Rack ratio is 16.8:1 for FE2 cars, and 15.3:1 for FE3. At just over 14 inches in diameter, the ATS' steering wheel is the smallest GM makes.

Range

Four models will be available - Base, Luxury, Performance, and Premium.

Premium model comes standard with Bose sound and satellite navigation.

Options include a new connected infotainment system called CUE, for Cadillac User Experience.

Available safety features include adaptive cruise control, brake assist, and lane departure warning.

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ATS UNDER THE SKIN

THE ALPHA SCENARIO

What the new architecture could mean for GM

If you love driving, the new Alpha architecture that underpins the Cadillac ATS could well be the single most important investment in hardware GM makes this decade. The lightweight Alpha architecture ensures rear drive cars have a future at GM despite tougher fuel economy targets worldwide. And not just in terms of variations on a baby Cadillac theme.

"It's scalable," admits Dave Leone, vehicle line executive for Global RWD and Performance Vehicles at GM. "In both directions." That's extremely significant, because what Leone is saying is Alpha can be configured to underpin cars that are smaller or larger than the 3 Series-sized Cadillac ATS. And, remember, Leone is the man ultimately responsible for all the next-gen rear drive and performance cars coming from GM over the next decade, from Corvette and Camaro to Cadillac CTS and Holden Commodore.

Reading between the lines, and it's clear Alpha will be scaled up to underpin the next-gen CTS, which will grow in size slightly over the current car to bring it more closely in line with 5 Series BMW and E-Class Mercedes. A slightly larger Alpha will also probably be used for the next-gen Camaro, which needs to become leaner and trimmer not just to compete with Mustang, but to boost its sales potential in export markets.

Corvette will remain a spaceframe car, and the Holden Commodore and forthcoming full-size Cadillac sedan will likely move to a second-generation Zeta architecture with lots of lightweight steel in the main structure, and the ability to use lightweight aluminum suspension components on the Cadillac version. So what else could Alpha be used for?

Well, scale it down, and you have the basis for an affordable baby Corvette -- a smaller coupe and roadster with V-6 and four-cylinder power that could support GM's big banger sports car in much the same way Boxster/Cayman support Porsche's 911. GM wants to give Corvette more of a unique brand identity, to give it a little more distance from the quotidian Chevrolet brand, particularly in export markets.

Stingray, anyone?