BMW is proud of it’s 3 series. The 3er accounts for 1 out of 3 BMW sales worldwide and has accounted for 50% of all US BMW sales since its introduction. And because of its success other premium auto makers have targeted it.

And Cadillac has taken the approach of a direct assault. The new ATS is within fractions of being the same physical size of the F30 3er. It uses a set of four cylinder and one six cylinder engines to power it (V6) and it is available with a manual transmission.

We had a chance to spend a few moments with Tom Prevost, the interior designer of the ATS, on the show floor. The mix of materials in the interior looked good, especially the exposed stitching. They have a good mix of wood, leather and chrome (on real metal – not plastic, the heat transfer when hand touches metal is there), and it looks good.

While we haven’t had a chance to drive one, the specs read like an F30 3er. Five link rear, MacPherson struts up front, rear wheel drive (optional AWD), and a ZF electric power assisted steering rack (the same basic ZF unit that BMW uses). Weight balance is 50/50 and of course the Nurburgring is evoked when discussing suspension tuning. Oh and Brembo brakes all around.

The four cylinder options include a 2.0L Turbo with 270 HP, the V6 produces 318 HP. An ATS 28i and ATS 35i? The 2.0L Turbo delivers 135 bhp/liter, which is a lot of output per liter of displacement. Cadillac also did its due diligence to save weight using an aluminum hood, magnesium alloy engine mounts and elsewhere throughout the car.

The interior uses premium materials, the stitching details are real (not embossed, as on some premium pretenders). They use real wood and we got a pleasant surprise when we touched the metal trim. It felt cold, meaning it was real metal, not shiny plastic. The seats felt good, but not as firm as BMW’s. The The is a large navigation display in the center stack plus an interesting hideaway cubby hole behind the HVAC controls. You can stash your iPod/MP3 player behind it (there is a USB port at the rear of the compartment).

Tom Prevost mentioned that the ATS was seeking elegance in both interior and exterior design. He remarked that they are using premium materials and blending them harmoniously in the interior. It’s a sporting elegance (and the car we sat in was equipped the six speed manual gearbox, a Tremec unit).

It is a different approach than BMW and conforms to Cadillac’s Art & Science approach to design. We’ll have to wait to sample one before we pass judgment. But as some wise BMW spokesperson said to BMWBLOG this morning, ‘every time the competition compares itself to BMW, it strengthens the BMW brand.’