I use my car for business and do a lot of highway driving, so it makes sense for me to buy used and drive the car forever. My GTP has been my favorite so far! Fantastic acceleration, excellent handling and very comfortable heated leather w/ 8-way power seats. After 55,000 miles, I have has no major mechanical issues, leaks or failures. I put Michelin HydroEdge tires on it which made a dramatic improvement over the Goodyear Eagle LS tires with which it originally came. It returns about 18- 22 mpg city and 27-30 mpg hwy and still able to run high 14-second quarter mile times (comparable to stock Mustang GT performance). For the money, a well-maintained GTP is the best used car value!
I love the 240 HP 3.8 V6, FWD pulls through 8" of snow with no trouble, great stereo, power everything, HVAC keeps cabin comfortable year-round and fat sway bars allow for twisty road fun - along with copious amounts of torque from the engine. There is a large enthusiast following for Grand Prixs.
The headlights are marginal and tend to fog inside the lenses in wet weather. There is a large amount of plastic in the interior with tends to creak in cold weather. The cup holder situates beverages very high in the console making it impossible not to spill with your elbow while operating shifter.