In my humble opinion, this is by far the best car for the dollar. I have owned over 50 cars in the last ten years, so I believe that I speak from some experience.
In purchasing this car, my goal was to find a vehicle that approached my wife's 2003 Jag S-type 4.0 in handling and performance, but at a reasonable cost. I drive entirely too much to justify depreciating a $50,000.00 car in a year or two. After some research and minor mechanical work, I believe that the GTP now exceeds all aspects of my wife's car, with the obvious exception of style.
There is a plethora of aftermarket performance parts available for the GM W-body, including parts from GM Performance. For a meer $350.00, I was able to upgrade the front and rear sway bars, rear suspension arms, add larger rotors and add strut tower braces through GM Performance. This gave the car a much more stable stance and confidence in braking, and all the parts were direct bolt-ons. I also upgraded the calipers, through US Brake, which made the biggest difference in the brake department for only $150.00. However, the biggest difference was the addition of GM's upgraded adjustable strut/spring package. This gave the car a more solid feel, and pushed the car into the Jag category of handling. This is a $700.00 option through GM, and gives 90% of the performance of the Jag's CATS system that costs $3,300.00.
The acceleration from the factory was superb, but with an additional $500.00, it was downright fierce. I fabricated a filter housing, added a K&N filter, reflashed the PCM, used a smaller pulley, and added the GM performance exhaust. The resulting combination of additions resulted in a car that beats most balding Corvette drivers who are asleep at the red light.
The fit and finish of the body are excellent for GM, but OK for the industry.
The 1999-2002 W-body Pontiac Grand Prix is probably the best purchase for the dollar right now, if you are mechanically inclined. There is a price to pay for having a dependable car that performs superbly. Some of us prefer (or can only) pay in cash, others prefer payment in sweat and grease. If you think you can change spark plugs, you can easily maintain this car, which looks great and is unbelievably cost efficient... I have $12,000 in my car, and it only has 15000 miles on it. I fully expect it to last 200000 miles, as my prior car did. It was a Buick Rivera, with the same 3800 Series II engine and Eaton supercharger.