Infiniti's current advertising spots begin with a Shodo brush stroke of a car silhouette, the designer's first representation of how a new car will look. With the IPL -- Infiniti Performance Line -- the brand puts figurative pen to paper and begins to sketch out a new, high-performance sub-brand. In creating the IPL, Infiniti is following well-established practice in the luxury-car arena. All of its major rivals already have a family of extra-sporty variants: M for BMW, AMG for Mercedes-Benz, S and RS for Audi, the V-series for Cadillac, and the nascent F models for Lexus. Given its comparatively small global sales footprint, however, Infiniti is starting small -- as a package, the IPL G Coupe is a considerably more modest effort than any of those specialty machines.
The IPL debuts as a single model, the G37 coupe. It's based on the G37 Coupe Sport 6MT, which already comes with the premium and navigation packages. The IPL treatment starts in the engine room, where engineers were able to coax a bit more out of the already high-achieving 3.7-liter V-6. Horsepower increases from 330 at 7000 rpm to 348 at 7400 rpm, while torque is bumped up to 276 pound-feet from 270. A less restrictive exhaust system is fitted, which Infiniti claims makes the engine freer-revving at high rpm. Buyers choose a six-speed manual or a seven-speed automatic with shift paddles.
Given some stick, the 3.7-liter roars to life, flinging the coupe down the road. Despite the retuned exhaust, this isn't the most mellifluous six, but it's hardly offensive. The six-speed manual has short throws and a satisfying mechanical heft that's matched by the effort of the clutch. The seven-speed automatic operates with flawless logic (holding gears indefinitely if the lever is first moved into manual mode, returning to Drive after a few moments if it's not).
The suspension is stiffened, by twenty percent up front and ten percent at the rear, compared to the base car. The brakes, 14.0-inch vented front discs squeezed by four-piston aluminum calipers and 13.8-inch vented rear discs with two-piston aluminum calipers, are from the sport package; so too is the limited-slip differential.