Mercedes-Benz added a second midsize sport-utility vehicle for 2006--a shapely crossover-type wagon with all-wheel drive and either V6 or V8 power. Built in America, the R-Class shared its basic structure with Mercedes' more conventional M-Class SUV, but it seated six instead of five and was 12 inches longer in wheelbase--15 inches longer overall. R-Class competitors included the Cadillac SRX, Lexus RX, and Volvo XC90. Two models were offered: the R350 with a 268-horsepower V6 engine, and the R500 with a 302-horsepower V8. A seven-speed automatic was the sole transmission. Both R-Class models had all-wheel drive, which lacked low-range gearing. Antilock four-wheel disc brakes and antiskid/traction control were standard. Front side airbags and head-protecting curtain side airbags that covered all three seating rows also were installed in each model. The R350 rode on 17-inch wheels, versus 18-inch for the R500; 19-inch tires were available for both. Seating was set up in a 2-2-2 arrangement, with folding second-row buckets and a folding 50/50 split third-row bench. Leather/vinyl upholstery was standard. R-Class models had a rear liftgate without separate-opening glass. Mercedes' Tele Aid assistance was available for the R350 and standard in the R500. Available for both were a navigation system and steering-linked xenon headlamps.