Kelley blue book is a registered trademark of kelley blue book co., inc. Reviews: * strong yet fuel-efficient v6; generous rear legroom; lengthy standard features list; competitive price. The rdx is equipped with a 3. 5-liter, i-vtec v-6 engine, that produces 273 horsepower. Despite its power it remains fuel efficient with the front-wheel drive model getting an epa rating of 20 mpg city, 28 mpg highway, and a combined 23 mpg. The all-wheel drive version is impressive as well with 19 mpg city, 27 mpg highway, and 22 mpg combined. The engine in the rdx comes with variable cylinder management that automatically makes changes to the number of cylinders used at any given time. The rdx comes standard with a sequential sportshift automatic transmission with steering-mounted paddle shifters. The driver and front passenger get dual-level heaters in seats and dual-zone climate controls. Leather Seats