Nissan has officially released details about changes to the Infiniti G lineup, including a boost in power to the G Sedan, all-wheel-drive for the G Coupe, and a convertible variant to be launched at the Los Angeles Auto Show this November. The G37 convertible will share its design with the coupe and will feature a three-piece retractable hardtop design, as well as revised HVAC controls for a more inviting experience whether the top is up or down.

The new G Sedan—respectfully renamed “G37”—will receive a 3.7-liter V-6 engine. The new powerplant will produce 328 horsepower, which is a boost of 22 horses over the current G35. The G Sedan will continue to be available in base, sport, and all-wheel drive variants and will be offered with a six-speed manual or new seven-speed automatic transmission. The sedan will also be offered with larger brakes and calipers, a revised eighteen-inch wheel design, and Scratch Shield paint.

While the G37 Coupe goes largely unchanged, it now benefits from Infiniti’s ATESSA E-TSÔ all-wheel drive system, previously only available on the Sedan. Infiniti will also be offering the new seven-speed slushbox on the G37 Coupe, as well as the standard short-throw six-speed manual.

No information on pricing has been released at this time, but look for the G37 Coupe and Sedan to go on sale this September. Click through for Nissan's official press release.

+ Autoblog: Nissan confirms G37 Sedan, G37 Convertible and G37x Coupe

INFINITI ELEVATES 2009 G LINEUP

When you have a vehicle line – say the Infiniti G – that has chalked up award after award, topped comparison test after comparison test, and endeared itself to a growing legion of passionate owners, what do you do for an encore? If you happen to be a world-class performance luxury brand – say like Infiniti – the answer is simple: Everything. The popular Infiniti G roars into the 2009 model year with an extensive array of changes, including:

    * The addition of an all-new Infiniti G37 Convertible model, slated to launch in the first quarter of 2009
    * A new 328-horsepower 3.7-liter V6 engine for the Infiniti G Sedan – now designated the G37 Sedan
    * A new all-wheel drive model for the Infiniti G Coupe, the G37x
    * A new 7-speed automatic transmission for all Infiniti G models (6-speed manuals transmissions also available)

"A little success makes you want to try harder. A lot of success makes you want to blow the doors off the competition again – which we're poised to do with the new, intensified Infiniti G lineup for 2009," said Ben Poore, Infiniti's vice president of marketing. "Year after year we strive to offer our customers one of the freshest product lineups in the industry – which we've done again in 2009 with the new second-generation Infiniti FX, upcoming G Convertible and the enhanced G37 Coupe and G37 Sedan."

2009 Infiniti G37 Convertible

The all-new G37 Convertible, the first-ever open-air G, is set for a mid-2009 model year introduction. Based on the current G37 Coupe, the G Convertible promises stunningly seductive styling and G-worthy dynamic performance. The new G37 Convertible will feature a three-piece automatic retracting hardtop, to keep a coupe-like roofline, and available unique interior treatment. Audio and HVAC systems have been enhanced to provide an inviting experience with the top up or down. The all-new Infiniti G37 Convertible is set to make its world debut at the 2008 Los Angeles Auto Show in November.

2009 Infiniti G37 Sport Sedan

The Infiniti G premium high-performance sport sedan receives a significant upgrade under the skin in 2009 with the addition of a new VQ37VHR "VVEL" 3.7-liter V6 rated at 328 horsepower. It is mated to a new 7-speed automatic transmission or close-ratio 6-speed manual transmission.

Now designated as the Infiniti G37 Sedan, other major changes include new available sport brakes with 4-piston front/2-piston rear calipers and large 14-inch front and 13.8-inch rear rotors, a new sport 18-inch wheel design and standard Scratch Shield paint (self-healing clearcoat finish).

The 2009 G37 Sedan is available in four models – G37, G37 Journey, G37S Sport 6MT and G37x AWD. It goes on sale in September 2008.

2009 Infiniti G37 Sport Coupe

For 2009, the G37 Coupe's performance envelope expands with the addition of a new G37x AWD model with advanced ATESSA E-TSÔ all-wheel drive system. Also new for 2009 is a 7-speed automatic transmission with Drive Sport (DS) Mode and Downshift Rev Matching (the G37 Coupe is also available with a 6-speed manual transmission).

All 2009 G37 Coupes receive standard Scratch Shield paint (self-healing clearcoat finish). The 2009 G37 Coupe is available in four models – G37, G37 Journey, G37S Sport 6MT and G37x AWD – each with standard 330-horsepower 3.7-liter VQ-series V6 with VVEL technology. It goes on sale in September 2008.