Portholes from Buick's past return for 2003 on its flagship sedan. Park Avenue comes in base and Ultra models, both with a V6 and automatic transmission. Ultras have a supercharger for more power. ABS, self-leveling rear suspension, and leather upholstery are standard. A front bench provides 6-passenger seating; bucket seats are an Ultra option. For '03, Ultra gets three chrome-plated "VentiPorts" on each front fender. Associated with Buick since 1949 and last seen in the 1980s, these design icons also increase engine-compartment airflow, Buick says. Other retro additions to Ultra are a "waterfall" grille, tri-shield Buick insignia, and chrome exhaust tips. Optional on the base Park Avenue and now standard on Ultra is the Gran Touring Package that includes a firmer suspension. Ultra also replaces 16-inch alloy wheels with new 17-inch chrome-plated wheels and gets interior-trim revisions, including a woodgrain steering wheel. Optional on the base Park Avenue and standard on Ultra are OnStar assistance, StabiliTrak antiskid system, traction control, and a tire-pressure monitor. A rear-obstacle-warning system is optional on both.