General Motors Corp. left the best for last.

The 2008 Buick Enclave, born from the same engineering that created seven or eight passenger crossovers for Saturn and GMC, is the most refined and sophisticated of the bunch.

In the “Bonanza” of crossovers, the Enclave would be Adam Cartwright to the Little Joe Outlook and Hoss Acadia — a happy but distinctively different brand of brothers.

For those unfamiliar with the cowboys, Adam was always the smarter, more successful sibling. Like Adam, the Enclave is quieter, more luxurious and probably recites Robert Frost in its spare time, while the more boisterous GMC and Saturn play cards and watch Tigers games.

The cool, smooth lines of the Enclave’s exterior carry country club airs. From its waterfall grille and sharply angled headlights (with Xenon high-intensity bulbs) to the chrome hood ports and bubbly windshield, the Enclave’s face projects just enough snobbery to fit into the luxury crossover segment but not offend.

It also comes in at a reasonable price. With a starting MSRP of $32,790, including shipping, it undercuts the Acura MDX ($40,665), the five-passenger Lexus RX 350 ($38,115) and the Audi Q7 ($40,620).

Unlike the some of GM’s previous SUVs, such as the drab Rendezvous and the “what the heck is that” Pontiac Aztec, the new threesome hit every mark in design.

The Enclave, which started filling showrooms last month, caught more than a few appreciative stares during the week I tested a $37,780 CXL model with front-wheel drive.

Its sloping roof, long wheelbase (119 inches) and wide stance (79 inches) maintain an elegant but strong appearance. Those dimensions also contribute to its smooth ride.

Enclave is a quiet ride

Like its siblings, the Lansing-built Enclave is powered by GM’s 3.6-liter V-6 mated to a six-speed transmission. But unlike the Acadia and Outlook, the Enclave is much quieter.

It’s common knowledge in the automotive industry that consumers equate quiet ride to luxury and quality, and the Buick ascends to crazy quiet levels. Perhaps it was all of the additional dampening materials installed and the streamlined body cut road and wind noise to SAT test-taking levels. There were a few times sitting at a light that I had to check whether the engine was still running; it was.

Buick calls it QuietTuning — though that sounds more like a marketing term than something engineers would come up with over coffee. Whatever they call it, it works. Even the Enclave’s glass is made in three layers, with a soft, transparent center between two layers.

Buick installed special engine mounts to cut down vibrations from the 275-horsepower engine. It’s more than enough power for the nearly 5,000-pound crossover.

The weight doesn’t appear to impact the Enclave’s gas mileage. It manages to get 16 miles per gallon in the city and 24 mpg on the highway. (The all-wheel drive model gets 22 mph on the highway.) Not bad numbers for such a large vehicle.

The highway mileage beats the lighter MDX and heavier Q7, and both of those vehicles still use 2007 EPA numbers, which require less stringent testing.

The Enclave glides over railroad tracks and the perpetual construction on Interstate 75. Acceleration is fast, but not quick, meaning it merges into highway traffic well and passes easily, but don’t bet its title at a drag strip.

The push-button sequential shifting feels awkward, though it works fine and adds some pep. If you’re going to try fake shifting, you should at least have the illusion of a gear shifter.

The six-speed transmission is silky, riding through the gears effortlessly and the handling is very good for such a large vehicle. It drives much smaller than its size — but can still tow 4,500 pounds.

It offers plenty for anyone

But the Enclave isn’t about driving; it’s about enjoying the ride. And the interior lets you do just that.

It’s comfortable, well-crafted and elegant. It mixes real and faux wood trim to make it feel like a polished piece of handmade furniture. You half expect to be able to pull a writing desk out of the dash. The perforated leather seats add to the vehicle’s panache.

The dash curves gracefully along the top — almost like an old mantel clock, though the real analogue timepiece was a little difficult to read. The other gauges are much more appealing, lit with soft green light.

The Enclave can carry seven or eight passengers, though I would recommend the standard captain’s chairs for the second row, making it nearly as comfortable as the front. The seats allow access to the third row through an opening between them, and they also incorporate GM’s SmartSlide, which folds the chair and moves it forward by pulling one lever.

The second and third rows fold flat, creating 115 cubic feet of space, plenty of room for weekend projects.

One omission was the second row lacks anywhere to hang dry cleaning. Even the Cartwright boys had saddle horns.

Apparently, GM ran into problems accommodating side curtain airbags and the handles, so it put small hooks in the back for items like starched shirts. This oversight was noticed by some of GM’s top people and could be rectified quickly.

Whether transporting family or things, the Enclave comes loaded with safety features, including stability control, anti lock brakes, two sets of front air bags and side curtain air bags for all rows. It comes with five-star crash test rating.

Packing a lot of standard features in the well-sculpted vehicle could help the brand lasso some younger buyers, something Buick wants and needs, to do. Already, Buick says buyers are 10-15 years younger than typical Buick customers, who are often honored by Willard Scott and Smucker’s.

The Enclave’s success, however, will be measured over the coming years not merely the next few months.

It certainly has the makings of an excellent vehicle. Its smooth quiet ride and opulent interior is something any saddle sore Cartwright might enjoy cruising around the Ponderosa.

2008 Buick Enclave

Type: A front-wheel drive large crossover SUV. All-wheel drive available.

Trim levels: CX, CXL

Retail price* $32,790 — $45,000

Engine: 3.6-liter, 275-horsepower, 251-pound-feet torque

Transmission: 6-speed automatic, includes sequential shifting

EPA mileage

FWD: 16 mpg city / 24 mpg highway

AWD: 16 mpg / 22 mpg

Notes: GM includes a four-year 50,000-mile bumper to bumper warranty and five- year 100,000-mile powertrain warranty.

*Includes $735 shipping

Report card

Overall: *** 1/2

Exterior: Good. Flowing lines from front to rear gives the Enclave a streamlined look and distinctive ports add style.

Interior: Excellent. Well crafted, elegant and comfortable.

Safety: Excellent. Front and side air bags. Stability control, traction control and antilock brakes.

Performance: Good. Handling and ride good for a large vehicle.

Pros: Extremely quiet on the road. Utility makes it a good all-around luxury vehicle.

Cons: Heavy curb weight.

Grading Scale

Excellent: **** Good: *** Fair: ** Poor: *