Shoppers who savor the idea of sport-utility motoring but need extra space have no alternative but to turn to General Motors. That's what GM's promotional folks claim, at any rate, though a relatively roomy Ford Explorer or Jeep Grand Cherokee might fill the bill for some families.

To capture this segment of the market, GMC launched the full-size four-door Yukon last year, joining its longer-lived two-door stablemate. Chevrolet's Tahoe is a near-duplicate, also offered in both two- and four-door format, with two- or four-wheel drive. Two-wheel drive is new to the two-door model; formerly, only four-wheel drive was available. In the size race, both fit squarely between the Blazer/Jimmy compact and the big-bruiser Suburban wagons. Squint your eyes, in fact, and the difference between a Yukon and Suburban begins to evaporate, despite the latter's extra 20 inches of steel.

Interiors have been borrowed from the full-size Sierra pickup, including a driver airbag and right-side A-pillar assist handle--a sensible addition, as climbing into full-size models can be a chore. Rear passengers get new heat ducts this year, and illuminated entry is now standard. Seat belts are height adjustable to fit many differently sized people, and 4WD models can be equipped with an electronic shift mechanism that is activated by pressing a switch on the dashboard. An electrochromic rearview mirror keeps bright lights out of drivers' eyes. Speaking of lights, the ones on the Yukon are on all the time, thanks to GM's obsession with daytime running lights.

The insanely popular Yukon four-door, and the sporty two-door, receive a new gasoline engine this year. Called the Vortec 5700, it pumps out 50 more horsepower and 25 foot-pounds more torque than last year's 5.7-liter V8. Two-door Yukons can also be ordered with a 6.5-liter turbodiesel engine. Manual shift, too, is offered only on two-door models. Four-door owners enjoy the smoothness of GM's four-speed automatic transmission, with electronic controls. Yukon four-doors can have either panel-style rear doors or a tailgate with lift-glass. Two-door 4WD models get passenger car tires that reduce noise and improve the ride.

Naturally, though, you can still expect truck-style ride and handling, but reasonable comfort on the road. General Motors expects to have this market niche to itself for another year or more, until Ford and Dodge release SUV's a tick larger than the Explorer and Grand Cherokee. Not a bad deal, this Yukon, and think of the juicier 5700 engine as your reward for waiting so long to get your hands on one.