This is what a07 Pontiac Grand Prix GXP is about ..
The GXP powerplant is the LS4 V8, a 5.3 L Displacement on Demand (active fuel management) engine based on the LS1 block. Output of this version is 303 hp (226 kW)/323 lb·ft (438 N·m). It has a shortened crankshaft, and a host of other modifications to make it fit into a front-wheel-drive vehicle. The GXP also has a 4-speed automatic transmission with paddle-style TAPshift, heads-up display, vented cross drilled brakes with PBR calipers, performance tuned suspension with Bilstein gas-charged struts (sits about 9 mm (0.4 in) lower than other GP models), Magnasteer II, and StabiliTrak dynamic control system. Also, the DIC will display G-Force (maximum achieved for lateral, acceleration, and deceleration) information when the car is not moving. Cosmetically, the GXP differs from the other models with more aggressive bodywork including a different front clip, wheel well cooling vents on the front fenders, a different rear bumper, and twin-dual polished exhaust. The Grand Prix GXP also offers a unique feature of the different-width 18 in (46 cm) polished Alcoa Forged aluminum wheels. The front wheels are 8 in (200 mm) wide, and the rear wheels are 7 in (180 mm) wide. This from the Wikipedia about the 05 gp GXP .. Wikipedia say this about the 2007 gp GXP ..2007Edit
For the 2007 model year the model remained Base, GT, and GXP. Also, the active displacement management capability on the 5.3 L V8 (GXP) was renamed to "Active Fuel Management" from "Displacement on Demand", while the GXP trim includes a 303 hp (226 kW) V8 engine with a firmer suspension, performance tires, heated leather seats, a heads-up display, and 18-inch (460 mm) wheels. My questions are about these features and trim model.