2006 Infiniti M45 Sport

Sport/luxury sedans? It's like this: If you want to be a player, you need something that not only delivers a lot of high-tech creature comforts and martini-smooth country-club cred, but also is snappy and civilized through the switchbacks. Germany has owned this territory for years--Benz, BMW, and Audi--but Jaguar and now Cadillac are gnawing around the edges. The Japanese? Lexus, Infiniti, and Acura have all delivered on the luxury, but the sport side of the equation has been a bit, well, John Kerry: not quite there at the end.

Enter Infiniti's new M35 (V-6) and M45 (V-8). The four-door M slots in above the six-cylinder-only Gs and below the flagging flagship Q45 and goes on sale this spring. The specification sheet checks the right boxes: class-leading horsepower, standard 18-inch wheels and 245 section tires, five-speed manumatic transmission, a sport package that offers grippier rubber, sharper steering, and stiffer suspension. It's a player.

What hits you immediately is that the M was conceived as an Infiniti. While there'll be a decontented, six-cylinder Nissan variant (named Fuga) sold in other world markets, the familial connection to the G, FX, and Q is clear and legit. The M is built on a larger, updated, and structurally stiffer evolution of the FM (front-mid-engine) platform that underpins the G35--no bad place to start. The exterior design is expressive and well detailed without being gimmicky. The trunklid, hood, and doors are stamped of aluminum to save weight.

We've never met a horsepower we didn't like, and the M is likeable indeed. The M35 makes use of Nissan's oft-praised 3.5-liter VQ-family V-6, rated at 280 horsepower. By comparison, the Cadillac STS's V-6 is good for 255, and the 530i's inline-six puts out 225. Acura's tech-savvy new RL has a 300-horsepower V-6, but there is no V-8 alternative. The M45 packs the Q's 4.5-liter, DOHC V-8, cranking out 335 horsepower (final spec had yet to be decided as we went to press). Compare this with BMW and Cadillac's V-8 variants, rated at 325 and 320 horses, respectively. Both M engines are backed by a five-speed manumatic transmission, which incorporates a snickety short-throw shifter and programming that delivers a throttle-blip with each downshift, just like the best auto-clutch manuals and F1 drivers. The M35 will be offered with optional all-wheel drive, a feature that's proven popular on the G35 since it was added last year.