All-new for 2007, the RDX slots below the MDX in Acura's lineup of luxury SUVs. Powered by a 2.3-liter turbocharged four-cylinder, the RDX produces 240 horsepower and achieves 19 mpg in the city and 23 on the highway. Standard is a five-speed automatic transmission, as well as side airbags for the front passengers and curtain airbags for both rows. Electronic stability control, as well as road-gripping all-wheel-drive, helps keep the RDX on the road.