15. Pontiac Grand Prix GTP (1997-2003)
The Pontiac Grand Prix GTP may have looked like just another family sedan, but underneath its modest exterior was a powerful supercharged 3.8-liter V6 engine putting out 240 horsepower and 280 lb-ft of torque. This impressive powertrain allowed the Grand Prix GTP to sprint from 0 to 60 mph in around 6.6 seconds, surprising drivers of more expensive sports sedans. Its strong mid-range acceleration and comfortable ride made it an ideal sleeper car, easily rivaling contemporaries such as the Nissan Maxima SE and Ford Taurus SHO. Despite its capabilities, the GTP remains an overlooked performance bargain today.
Source: MotorTrend