Something always seemed to look a little odd with your model and I didn't know what it was until last night when I noticed it didn't have the seams or threads. Can't believe I didn't notice before, hehe. Well, I've never modeled a car before so I don't really know how you'd go about adding those details with the body being already modeled. Try sending younglion a private message to see if he has any suggestions, I don't think he would mind.
You seem like you've really learned alot from this project already. I know you've been working and tweaking it for awhile now but don't worry, over time, you'll get better and faster. If you're learning and improving, which you are, then you're definitely going in the right direction.
Don't be satisfied with what you can do but rather strive to do the things you can't do!