They range from high-volume entries by Toyota, Honda, Ford, and Chevrolet to more luxurious utility vehicles from the likes of Audi, BMW, Mercedes-Benz, and Range Rover. But only two compact crossovers offer the option of a diesel engine. Both are German, and we've now driven each one. This first of two reviews covers the 2014 Audi Q5 TDI, a new-this-year diesel option for the Q5 crossover that's been with us since 2009. We'll review the Mercedes-Benz GLK250 BlueTEC separately. The diesel Audi crossover is rated by the EPA at 27 mpg combined (24 mpg city, 31 mpg highway)--and like many diesels, it's able to exceed its EPA rating in highway use. In fact, on our 240-mile test cycle, we managed to register a remarkable 35.1 mpg on the vehicle information display. For an all-wheel-drive, five-seat utility vehicle with good performance and a lot of luxury features, that borders on the amazing.

We should underscore here that our usual test cycle is two-thirds or more high-speed highway running, where diesels excel. The Q5 TDI as delivered to us, after a few dozen miles in transit, registered 25.0 mpg. Over our first 120 miles, including some hilly mountain roads, we registered only 24.0 mpg, with intermittent readings from 23.6 to 30.3 mpg. But on the return leg of the trip, with free-flowing highway traffic at about 75 mph, the fuel efficiency rose steadily--staying pegged right at 35.1 mpg for the last 40-plus miles. After the 240-mile trip, we still had about two thirds of the 19.8-gallon fuel tank remaining, according to the fuel gauge. More than that, and unlike the Chevrolet Cruze Diesels we've driven, the Q5 TDI has good pickup from a standing start and almost no power lag. Acceleration from 0 to 60 mph is quoted at just 6.5 seconds. Chalk that up to the 240-horsepower, 3.0-liter V-6 turbodiesel, which puts out a prodigious 428 lb-ft of torque. The Q5 TDI's diesel engine is paired to an eight-speed automatic gearbox whose ratios always seemed to provide the necessary power on demand.

If you鈥檙e an automotive enthusiast, then small luxury crossovers probably don鈥檛 light your candle. Still, the refreshed-for-2013 Mercedes-Benz GLK deserves your attention. Never a champion in the EPA fuel-economy department, the Mercedes-Benz GLK gets two significant upgrades in its engine bay for the 2013 model year. First, the GLK250 BlueTec is new to the lineup. Its 2.1-liter diesel four provides 190 hp and 369 lb-ft of torque. The rollout of more four-cylinder diesels in the U.S. 鈥檙e pretty psyched. And let鈥檚 be clear: Benz isn鈥檛 bringing its four-cylinder diesel here for just one car. Investing in emissions and crash compliance means you鈥檒l see the diesel four in the next-gen C-class鈥攁 mechanical cousin to the GLK鈥攁mong other vehicles. For folks who prefer gasoline power, the GLK350 is upgraded with the latest generation of Benz鈥檚 3.5-liter V-6 engine. Now featuring direct injection, the GLK350鈥檚 engine is good for 302 hp and 273 lb-ft of torque. The older V-6 made just 268 hp and 258 lb-ft. The GLK350 also picks up an engine stop/start system, a feature heretofore exclusive to Mercedes鈥?hybrid models and a few AMG cars.

As was the case in the past, the GLK350 comes only with a seven-speed automatic gearbox but can be ordered with either rear- or all-wheel drive. The chunky styling that distinguished the last GLK has now been softened, with a curvy new fascia setting a more graceful tone. This restyled schnoz also brings the GLK鈥檚 look in line with the appearance of other new Mercedes models, such as the M-class crossover. Not shockingly, the GLK gets this decade鈥檚 must-have automotive fashion accessory: LED daytime running lights. An optional package will upgrade the headlamps to the lighting equivalent of a NASA computer system, bringing an active cornering function, headlight washers, and automatic high beams that dim when cars or pedestrians are detected ahead. Benz鈥檚 boffins also restyled the GLK鈥檚 back end. The new taillights are now solid red, rather than the red-and-white sandwich of last year鈥檚 car. The lower fascia also is remodeled, with a chrome skidplate-type substance and integrated exhaust outlets.

For more style, an exterior AMG Styling package remains on the options sheet; it adds 20-inch AMG wheels, different LED running lights, aluminum roof rails, and tweaked fascias. In contrast with the gently massaged exterior, the interior of the GLK was hit harder by the metaphorical wrecking ball. A stylish new dashboard has been installed, with two circular vents in the center and a sweep of metal or wood spanning its width. A 5.8-inch display sits atop the center stack, while upgrading to the Multimedia package nets a seven-inch screen to display the latest iteration of Benz鈥檚 COMAND infotainment system. The screen in the IP has been upgraded to color, too. The dash looks nicer than the boxy, plasticky piece in the pre-refresh GLK, and should represent the same leap forward in material quality we saw in last year鈥檚 update to the cabin of the C-class. GLK fanatics may also notice that the console-mounted shifter is gone, replaced by a column-mounted gear selector. This, in turn, clears up some space on the center tunnel. A set of steering-wheel-mounted shift paddles are now standard.