Have a look at my F1 car and tell me what you think about it.
http://medlem.tripodnet.nu/Markuza/mg/http://medlem.tripodnet.nu/Markuza/mg/
This is a very good model. The shaders could do with a little work, i.e. making the wheel hubs a little less plasticy and the interior of the cockpit could do with tweaks but otherwise this is fine work. Why not try some more realistic renders showing the model as a "real" car not a model one. That would prove more of a test of lighting and I think provide a more satisfactory result. Try finding (or taking) a photo of some tarmac and comping your car in. I think that would be a natural extension of a project that shows a lot of promise.
Andrew
Thanks for your comment. I will try to make the things you said less plastic. Do you have a tip of a more realistic render, and it is free?
In the past I'd have suggested BMRT as the best free renderer out there. Sadly as of a few weeks ago it has been withdrawn so I'm at a bit of a loss to know what to recommend.
There's nothing fundamentally wrong with the renderer you're currently using and changing to another renderer will not magically make your work better.
You need to look at shots of real cars, check out how they are lit, directly and indirectly. Look also at some of the car renderings on this site, some are excellent, others aren't so good. Analyse what makes the good ones great and the why the others fail. Look at shadows, reflections, detail etc. etc.
There really is no secret formula to this. It requires time, patience, experience and a lot of experimentation. You've started really well, maybe it's time to do a bit of visual research and then dive back in.
Andrew
I have "listened" to your comments and tried to improve my project. I have added 2 new pictures on my site.
http://medlem.tripodnet.nu/markuza/mg/http://medlem.tripodnet.nu/markuza/mg/
Markuza
This is a real improvement. The bodywork looks great, and the cockpit interior looks very good. I'm still not too keen on your wheel hub shaders. I think your diffuse values may be too high. You could also try adding a very subtle blurry reflection to them? I also think that the tyre texture doesn't look right either. Small adjustments should do it. And I would add some bump-maps to the tyres to break up the surface a bit.
Keep going it's looking great. I would still try lighting it to comp into a photo, that's the real acid-test!
Andrew
Nice looking model. I would agree that if you tweaked the lighting a little, it could make it even better. Also, I'd recomend making it a little more dirty, and less perfect. I know that in reality, before a race they keep thier cars "perfect." But in this case, it would be more believable if it were a little less than perfect. Scrub the tires a littlle, add some wear to the wings from the wind blasting the front edges, try dirtying up the body work around the tires. You could also try playing with your spec map. Just some thoughts. Looks good though. Keep it up!
I have added 4 more images of my F1 car in the "My work" section, on my homepage. I have added some dirt (not finished with that) and made some other improvements, I hope 
http://medlem.tripodnet.nu/markuza/mg/http://medlem.tripodnet.nu/markuza/mg/
Markuza