The lower-body cladding is gone. The exaggeratedly ribbed taillights have yielded to modesty.

Even the passenger cabin is adult. Premium fabrics, leather and vinyl have replaced dime-store cloth and plastic. Simplicity has displaced clutter on the instrument panel. Now, everything is where it should be, clearly visible, easily within reach.

This is not the Pontiac Grand Prix of your muscle-car youth. Nor is it an underpowered, poorly tailored, highly polished weekend fantasy borrowed from a car-rental company. The 2004 Pontiac Grand Prix is so much better. It's a worthy contender for dollars spent on midsize sports sedans.

Yet, in its transition from adolescence to maturity, the Grand Prix has held tightly to fun. In fact, in body structure and suspension, the new car offers more smiles per mile.

The 2004 Grand Prix's body is discernibly more rigid than that of its predecessors. Credit goes to engineering touches such as the use of a magnesium beam to help support the instrument panel. The Grand Prix feels as tight as the best sports sedans from Europe and Japan. It handles as well as some of them, too.

I drove the GT and GTP cars, two of three versions currently offered in the Grand Prix line. A third model, the Competition Group (Comp G), is designed for weekend racetrack warriors, or for people who think they'd like to run with that crowd.

The Comp G was not available at this writing. No matter. I had fun enough in the GT and GTP.

Both the GT and GTP have front suspensions composed of McPherson struts, coil springs, lower A-arms (lateral suspension links in the shape of the letter A) and a solid anti-roll bar. Their rear independent suspensions include three-link coils over struts and an anti-roll bar. The GTP Comp G gets an upgraded version of the GT/GTP suspension system (for example, a larger anti-roll bar in the Comp G).

All of that tech talk comes down to this -- more stable, wiggle-free handling in curves, and more confident lane changes on high-speed expressways. There is no need to fear heavy trucks in the Grand Prix GT or GTP, because there is no need to be around those trucks in these cars. The Grand Prix can move!

The GT runs with a 200-horsepower version of General Motors Corp.'s venerable 3.8-liter V-6. It develops 225 foot-pounds of torque at 4,000 revolutions per minute. The GTP gets a supercharged, 260-horsepower iteration of that engine that develops 280 foot-pounds of torque at 3,600 rpm.

I prefer the GT. It's more straightforward, and you can run the thing on regular unleaded gasoline, vs. the premium unleaded required for the higher-compression GTP. But preference doesn't imply a willingness, or intention to reject -- not at all. I'd happily take any one of the front-wheel-drive Grand Prix cars on a cross-country trip to the West, and I'd salivate upon reaching the Wyoming border.

I'd especially like to make that run in late spring or early summer. Wyoming is beautiful that time of year and the highways, good gracious! You're looking at a legal 75 mph on interstates on clear, dry days -- on roads with long stretches of emptiness.

You really can enjoy a car such as the new Grand Prix on Wyoming's highways. Yes, indeed. You really can.