[In regard to the Civic] I like the pictures. The second one on the top is the best, I think, because there are bright colors on the traffic behind your car, which makes it stand out more. Nice wheels, too.
On this last set...brighten. That's a nice location for the shot, lots of color and such, but I think you need to take it up a notch or two.
Good pictures, keep 'em coming.
-Dahze
[Added note] When I'm setting up the shot in GT4, I usually crank the brightness up to around 6-7, which may help before you even take it to editing software.