Pontiac's G8 GT muscles in on BMW.

DETROIT - Pontiac can't get a break. It finally rolls up to the party in its G8 sedan -- with a big snorting engine under the hood, herds of leather in the cabin and a keg in the trunk -- only to find the festivities are over. The last drunk has staggered out. The pool is being skimmed. It's too much, too late.

Back in the halcyon days of 2002, General Motors had a plan for Pontiac. The once-proud division, tarnished by three decades spent selling restyled Chevys, would transform itself into the American version of BMW, building rear-drive performance cars without the high German prices. The G8 would be the flagship, and its role was to make such a notion seem not quite so preposterous.

But today, with GM's future in doubt, the G8 power-slides into unknown terrain. Some people at GM say this midsize sedan is the future face of a Pontiac unit that will be downsized and refocused. Some say the G8 is doomed to die in 2013, or that its V8 engine will be swapped for a less thirsty turbocharged four-cylinder. Others, including tightfisted members of Congress, insist that GM could never make a car this good in the first place.

The G8, which supplants the Grand Prix, was engineered in Australia, where the same basic car is the Holden Commodore. It's sold in two versions -- the base model (with a 3.6-liter V6) and GT (6-liter V8) -- with a super-high-performance GXP scheduled to go on sale by February.

At $28,875, the base G8 is a fine automobile, although light on power (256 horses) and heavy on weight (3,885 pounds) compared with a comparably set-up Nissan Maxima or Mazda 6.

Yet the base car suffers no visual slights. It has the same flared fenders and 18-inch wheels as the GT. It rides on the same impressive suspension, with struts in front and four links in the rear.

Mainly, though, the base model exists to remind you that for an extra $3,365 you could have had the GT. It offers two extra cylinders and 105 more horses, plus another gear in the transmission, larger disc brakes and a six-CD changer with MP3 playback.

Indeed, the GT is where the action is. This car is a class-jumper, a $32,240 four-door with the power and grace to hang with luxury-sport titans such as BMW's 5 Series.

Anyone who's driven a Pontiac in the last 30 years might read that sentence and think that GM piped nitrous oxide into my test car. But the comparison is defensible. Despite the yawning cultural chasm between Australia and Germany, the two nations have the sort of curving, open road systems that breed fantastically cohesive rear-drive cars.

And that is exactly what we have in the G8. Setting the tone is a cabin with a studied relationship among steering wheel, seat and pedals that make it easy to find the optimal driving position. The interior is all black and silver, and the controls are of seriously high quality. My one complaint is that too-thick windshield pillars make it hard to see through corners.

I know this because I was constantly seeking curves around which to toss this car. Pitched hard into a turn, the big Pontiac claws through the corner. It won't wallow or pitch or track wide of the intended line.

Like a BMW or Mercedes, the Pontiac is a heavy machine that feels stout and energetic rather than cumbersome. This is primarily because of its 50-50 front-rear weight distribution and its stiff structure, which frees the chassis to absorb bumps rather than to mitigate body flex.