NAPA, California — Citing high customer interest in all-wheel drive, Infiniti is adding a G37x coupe to the G lineup for 2009. And like the rest of the 2009 Infiniti G37 sedan and coupe lineup, the all-wheel-drive coupe will benefit from a new seven-speed automatic transmission when 2009 G goes on sale at the end of October 2008.This seven-speed automatic, which originally debuted on the 2009 Infiniti FX50, is standard on the 2009 Infiniti G37x coupe and sedan. Rear-drive Infiniti G37s can be equipped with either the seven-speed or a six-speed manual transmission.Like last year's five-speed automatic, the new seven-speed auto matches revs on downshifts. Paddle shifters are available via the Sport Package, but this option group isn't available on the G37x coupe or G37x sedan.Infiniti officials say they're expecting 30-40 percent of 2009 Infiniti G37 Coupe buyers to opt for all-wheel drive. 'The G37x sedan is at 40-percent-plus nationwide,' Jon Weiner, director of product planning, tells us.Consistent with the revised model name on the '09 sedan, all Infiniti Gs now have the 3.7-liter VQ37VHR V6 engine. In the 2009 G37 sedan, it's rated at 328 horsepower at 7,000 rpm and 269 pound-feet of torque at 5,200 rpm. In the G37 coupe, it makes 330 hp and 270 lb-ft at the same rpm thresholds.Infiniti has found another use for the 2008 Infiniti's G35's 3.5-liter VQ35HR V6. It's the new base engine in the 2009 Infiniti M35 with ratings of 303 hp at 6,800 rpm and 262 lb-ft of torque at 4,800 rpm. Last year's M35 offered just 275 hp at 6,200, though its torque rating was slightly higher — 268 lb-ft at 4,800 rpm.The company stopped short of putting the potent new 3.7-liter engine in the midsize M, because the 4.5-liter V8 in the 2009 M45 still makes only 325 hp. 'Of course, the torque characteristics would be different between the two engines,' says Weiner, 'but the typical consumer may not see that.'Rear-wheel-drive 2009 Infiniti M35s also get the new seven-speed automatic transmission, but the M35x and all M45s stick with the old five-speed automatic.Infiniti has not announced official pricing for either the 2009 Infiniti G37 or the 2009 Infiniti M35, which goes on sale in December 2008, but the base-level G37 sedan with the seven-speed automatic is estimated to cost $33,000, while the G37x coupe will be priced close to $38,500. The 2009 M35 is estimated at $44,500.What this means to you: Good times. The 3.7-liter V6 is an exciting engine, and the shorter-geared seven-speed automatic is a better match for it than the previous five-speed unit. — Erin Riches, Senior Editor