AS $3-A-GALLON GAS

has become the norm rather than the exception, people who once bought sport-utility vehicles to carry kids and gear are looking for that same versatility in smaller, lighter and nimbler packages. Carmakers have responded with a flock of luxury wagons that ride like cars but have the functionality and street presence of SUVs meaning available all-wheel drive and a wagon back for cargo. We test-drove four 2008 luxury crossovers with starting prices between $30,000 and $40,000 and Xs in their names: the Lexus RX 350, the current top-selling crossover; the Acura RDX; the Lincoln MKX; and one of the newest entries, the Infiniti EX35. These vehicles represent two distinct approaches to the 21st-century station wagon. While the Lexus and Lincoln target fans of old-school midsize SUVs like the Ford Explorer, the Acura and Infiniti strike a sportier attitude in styling and performance, aiming their vehicles at the successful BMW X3 compact crossover and people who prefer sedans but need more carrying space. Here's a look at how these X wagons stacked up.

The Acura RDX

The RDX is the luxury sibling of the highly successful Honda CR-V. But the same basic package that works so well as a Honda disappoints as an Acura. One reason: Acura's decision to substitute a turbocharged 240-horsepower, four-cylinder motor for a six-cylinder. The RDX simply isn't as smooth as rivals with two extra pistons. But it's a tad sippier on gas, with an EPA-rated mileage of 17 city, 22 highway. That's not much better than some larger SUVs but to be fair to Acura, all the luxury crossovers we drove tend to optimize performance over fuel economy. The RDX tosses in tech features such as an all-wheel-drive system that shifts torque from side to side and front to back, and real-time traffic information available through the navigation system. (Navigation is available only if you buy the RDX model with the "technology package," at a starting price of $37,410. The 2008 RDX without the techno-goodies starts at $33,910.) Ultimately, the RDX's busy ride and disappointing mileage put it fourth in this pack.

The Lincoln MKX

The Lincoln MKX looks like the Lexus RX's first cousin. Like the Lexus, the MKX has a sedate ride; to our ears it was quieter than the RX. The MKX is a smidge bigger in most key dimensions than the RX, although somehow the MKX delivers just 40.7 inches of front leg room, compared with 42.5 inches for the Lexus. Lincoln equips the MKX with the new Sync system for linking digital devices such as phones and iPods into the vehicle's audio setup. The MKX also boasts standard heated and cooled front seats, a parking assist that beeps when you back up too close to another car, and an optional all-glass "Vista" roof. But it also has its flaws. While the 3.5-liter six-cylinder delivers 265 horsepower through an automatic V-6 transmission, it's rated a dismal 15 mpg in city driving, 22 highway. Maybe that's because the MKX tips the scales at 4,400 pounds 300 to 400 pounds heavier than our other vehicles.

The Lexus RX

The RX 350 offers refined banality as an antidote to the unpleasantness of most modern driving. Lexus hasn't designed it to please auto critics; it's aimed at busy suburbanites who want a refuge amid the hurly-burly of runs from work to home to school to mall. On the highway the 2008 RX is smooth and forgiving. It carries more than 38 cubic feet of cargo best in this group. It has good resale value and a solid history of reliability. Why isn't the RX No. 1? Because while it's a good buy, at five years old the current generation is showing its age. Lexus needs to step up its game, and a redesigned RX is probably a year or so off.

The Infiniti EX

Infiniti refuses to play the crossover game like everyone else. The 297-horsepower EX35 rejects the boxy SUV formula established by Jeep. With its curved roofline and carlike stance, the EX35 is a sports sedan with a fanny pack. The EX lineup starts at $32,015 for rear-wheel-drive models and $33,415 for all-wheel-drive versions. Infiniti also promotes the EX35 as a wagon for the BlackBerry set. Our test vehicle included a camera system that displays an overhead view of your EX and the vehicles on either side, the better to park unscathed. It also featured an (annoying) system that beeped or automatically applied subtle brake pressure if we drifted out of our lane without signaling. Downsides: Only 3.3 cubic feet more luggage space than a G35 sedan with the rear seats up. And all the gizmos can push the price above $40,000, at which point you'll question the value of an electronic backseat driver. Still, Infiniti's new EX35 wins in this group because of its fresh design, spirited performance and price advantage over its most direct rival, the BMW X3. But all these brands should beware that consumers may tire of wagons with such lousy mileage ratings. The carmakers can do better, and should.

Infiniti EX35 Base Price: $33,415 Engine: 3.5-liter V-6, 297 hp Ride/Handling: Int./Ext. Design: Overall Rating: Comment: Mileage could be better (17 city, 24 highway), but the Infiniti's fresh silhouette, peppy 297-hp engine and lower base price give it the winning edge.