In an old country song, Mac Davis defines happiness as "Lubbock, Texas, in my rearview mirror."

At GMC, happiness may be seen as badge engineering in my rearview camera.

For the longest time, General Motors wrought a GMC vehicle by simply putting a GMC emblem on a Chevy. In recent times, it has made a serious effort to differentiate GMC models from their corporate cousins at Chevrolet, and take them a bit more upmarket in the process.

The new GMC Terrain compact crossover is a case in point.

While the Terrain shares its structure and mechanicals with the Chevy Equinox, its body is unique, as is its interior. So, it has significantly differentiated itself, and that's really all people want. Customers don't care, for example, that a Lexus ES350 is, essentially, a Toyota Camry V-6 with fresh sheet metal and a classier interior. The car has a different personality and appeal.

Because of their common mechanicals, the Terrain shares with the Equinox the honor of being the quietest, best-riding, most economical compact crossover on the market. The four-cylinder, front-drive model I tested had EPA mileage ratings of 22 city and 32 highway, which is better than the Ford Escape Hybrid. By using a clever wrinkle called "ECO-mode," I was able to get an astounding 37 m.p.g. in mixed driving on regular gas.

The Terrain is able to get that kind of number through the use of a small but highly efficient direct injection engine; the ECO-mode; a nifty, six-speed, automatic gearbox; and tires endowed with reduced rolling resistance.

By injecting the fuel directly into the combustion chamber - instead of the adjacent intake manifold port as in conventional port injection - the direct-injection system delivers a cooler, denser fuel charge that allows a power-producing increase in compression ratio. Also, it delivers the fuel to the precise spot in the chamber where ignition is optimal. This means more power and better economy. Direct injection adds cost to an engine, but the payback in performance and fuel savings is significant.

The other fuel saver of interest is the driver-selected ECO-mode feature, which saves fuel two ways. First, it locks up the automatic transmission's torque converter at a lower RPM, which means it is eliminating fuel-wasting slippage sooner. Second, it shifts into higher gears sooner, another fuel-saving tactic.

Speaking of good ideas, the Terrain uses an ingenious system to achieve its no-talking-in-the-library interior hush: Two microphones detect low-frequency sounds in the cabin. These sounds are then canceled by sounds from speakers in the car's audio system.

Further noise reduction was attained by using acoustic glass on the windshield and front side windows and employing triple door seals.

In addition to being quieter than its compact competitors (Ford Escape, Toyota RAV4, Honda CR-V, Jeep Liberty, and Hyundai Santa Fe), the Terrain has a more attractive and richer-looking interior.

The interior of the tester, a slightly upmarket SLE-2 model, was really quite handsome. The design employed soft, black and gray leather-look vinyl with red stitching and chrome and silver accents. The comfortable, supportive fabric seats used the same color scheme.

A compact that lives near the midsize border (GMC likes to mention the midsize Ford Edge and Nissan Murano among its competitors), the Terrain is a roomy five-seater. It has a generous 31.6 cubic feet of storage behind the backseats, and nearly 64 with the seats folded down.

The Terrain's blunt, macho exterior styling didn't move me as much as Cousin Equinox's sleeker look.

The 2.4-liter, 182-horsepower four that I drove gets from zero to 60 in a reasonable 8.7 seconds. For me, it wouldn't be worth the extra cost and reduced fuel mileage it would take to shave nine-tenths of a second off that number with the optional 3-liter, 264-horse V-6. Besides, the ECO-mode and noise-cancellation systems are available only on the four-banger.

The Terrain I tested was very nicely equipped, handled and braked well, and boasted a complete air-bag array and good government crash-test results. It got the maximum five-star ratings for side and frontal crashes, and four for rollover.

Terrain base prices range from $24,250 to $31,300 for the deluxe, all-wheel-drive model.

Excellent

2010 GMC Terrain SLE-2 (FWD)

Base price: $25,950.

As tested: $29,475 (including shipping).

Standard equipment: Includes 2.4-liter engine, six-speed automatic gearbox, 17-inch alloy wheels, the usual power assists, automatic headlights, OnStar protection.

Options: Heated front seats, remote starter, dual-screen rear-seat DVD player, sunroof.

Fuel economy: 22 city

and 32 highway.

Engine performance: Adequate.

Styling: A bit blunt.

Warranty: Three years/

36,000 miles bumper

to bumper.

The Ben Key: Four Bens, excellent; Three Bens, good; Two Bens, fair; One Ben, poor.

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Contact Al Haas at Alhaas@aol.com.