That last picture is just great
Tips:
Focus on the pixels more after you're done with the colors and general blur. I would take at least 20 minutes in zoom mode, with blur tool (3px brush size, opacity 30-40%), and just blur every pixelated edge you see. Be as precise as you can be, if you can you could even use a 2px brush size.
If I look at the picture, I see pixelated edges at the spoiler, where the rear window meats the background, and the fron wheels (what happened there?) and there's a terribly pixelated spot just above the mirror, on the hood of the car.
Wheels, if you take a picture like this in GT4 with high shutter speed, you should take 2 more shots with: shutter speed all the way down, aperature all the way up, and focus on a wheel. Do that again for the other wheel. Open the 3 pictures in photoshop, take the original, then take one of the wheel-blur pictures, and select the blurred wheel. Then move the selected area with a tool in the left menu (should look like an arrow with a sort of arrow-cross next to it) to your original picture. Do that with both wheels and you will have blurred wheels. Do this at the very beginning, and make sure to layer->flatten the picture untill you have only one layer left.
The car could've used a
bit more contrast and saturation. Just a bit though.
The colors of the background couldn't have been better
