Subaru introduced its largest-ever vehicle for 2006: a midsize sport-utility vehicle with available seven-passenger seating and a standard six-cylinder "boxer" engine. Similar in size to Toyota's Highlander, the B9 Tribeca shared its architecture and powertrain with Subaru's Outback and Legacy. Tribeca was the first Subaru SUV that could hold as many as seven occupants. Distinctive, if ultimately controversial, styling was led by a unique shield-shaped grille, inspired by the company's aircraft heritage. Considered a "crossover" model and billed as a "progressive SUV," Tribecas came in base and Limited trim. Both had all-wheel drive without low-range gearing. The sole powertrain consisted of a 250-horsepower 3.0-liter horizontally-opposed six-cylinder engine that mated with a five-speed automatic transmission, which incorporated a Sportshift manual shift gate. Seating for five was standard; a two-passenger third-row seat was optional. An antiskid system, antilock four-wheel disc brakes, and 18-inch alloy wheels were standard. So were front side airbags and head-protecting curtain side airbags that covered the first and second seating rows. Standard equipment included automatic climate control, a CD player, and power front seats. All Tribecas had a sunroof and 40/20/40 split folding second-row seats. Seven-passenger models added a 50/50 split folding third-row seat, rear climate controls, and heated front seats. Limited models added leather upholstery and an in-dash six-CD changer. Rear DVD entertainment was optional on seven-passenger models. A navigation system was available for Limited models. In addition to the Highlander, B9 Tribeca competitors included the Ford Freestyle and Nissan Murano.