The front-wheel-drive 2008 Pontiac Grand Prix sedan is available in two different models, both with their own powertrain. The base Grand Prix has a 200-horsepower, 3.8L V6 underhood, while the GXP model packs a 303-horsepower, 5.3L V8. Both engines come with a four-speed automatic transmission. The top GXP comes with a standard head-up display (HUD), which projects dashboard displays onto the windshield. The system is designed to enhance safety, but can be switched off if not desired. A performance-tuned suspension, 18-inch forged aluminum wheels, StabiliTrak stability control, and the Magnasteer II variable-assist power steering system are all standard on the GXP, which translates to a sportier overall driving experience. The GXP can accelerate from 0-60 in only 5.6 seconds, and its transmission features a TAPshift manual-shift function. All Grand Prix models have quite impressive fuel economy ratings. The base Grand Prix is rated at 28 mpg highway, and the V8 manages to get 16 city, 25 highway. A Special Edition Package adds a high-performance appearance to the base model, including an air dam, rear spoiler, body-color grille, and dual bright exhaust tips. The Grand Prix has an especially spacious interior, including a back seat capable of carrying three adults. The back seats are split 60/40 and can fold forward or have a pass through for narrow objects like skis for objects as long as nine feet. Both Grand Prix models have four-wheel disc brakes, but anti-lock is optional on the base Grand Prix. Front and rear side curtain air bags are optional on both models. The standard OnStar system includes GM's Advanced Automatic Crash Notification (AACN) system, which can make crash data available to 911 dispatch, depending on the situation. The service can also accommodate an optional Turn-by-Turn Navigation system.