NASHVILLE, Tennessee — Nissan's G Sedan is undergoing some changes for 2009, including a new designation as the G37 sedan, thanks to its new 328-horsepower 3.7-liter V6 engine.

The G coupe was first to receive the 3.7-liter V6 in 2008, changing its model designation from G35 to G37 coupe, but the sedan was a year behind in getting the upgrade. Now the 2009 G37 sport sedan not only gets the 3.7-liter engine, but drivers can choose between a new seven-speed automatic transmission and a close-ratio six-speed manual.

Other changes include new optional sport brakes with four-piston front/two-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, a so-called 'self healing' clearcoat finish.

On sale in September, the rear-wheel-drive 2009 G37 Sedan will be available in three models — G37, G37 Journey and G37S Sport — plus the all-wheel-drive G37x.

A base-level 2008 G35 starts at $32,250. Pricing for the 2009 G37 sedan has not yet been released.