Well, I think I am always honest with my opinion, so here goes:
First of all, you've got some quite nice images, I recommend you to open a gallery and start entering competitions so you can expand a bit more. Also, reading some of the tutorials posted in this section, would be of great value.
As for each individual picture, I don't need to say much about the last picture because it's very good. I like the composition and it's mood.
As for the first one, while I understand you've tried to capture the road length, I've cringed a little when I saw the bottom of the car cut out. It just doesn't end well, it would probably be better if the picture was in portrait format.
2nd - It's a pretty good and powerful image ruined by the use of the miniature filter. It's common mistake and risk to use the miniature filter as a complement for the blur, sometimes it ends fine, others don't. In this case it blured parts of the car that shouldn't be blured. IMO, I say, leave the miniature to it's porpouse.
3rd - I am not sure if the intention was to show the car drifting or sitting in the track like it would be in phototravel. If it's the latest, it's great! If it's the former (and I guess it is because of the smoke) then some "speed blur" may be in order. You should have lowered the shutter speed to something like 1/60.
4th - It's a good shot, I would probably put the center of the wheel a little more to one of the sides (not in the center of frame), but I don't have much to add about this one.
I hope this helps. Again, reading some of the tutorials in this section would help greatly.
let me know what you think ! 
[/url] Special Stage Route X_1 by [url=http://www.flickr.com/photos/nismor33/7566699644/]
Kyoto - Gion_1 by NismoR33, on Flickr[/IMG]/people/nismor33/]NismoR33[/url], on Flickr[/IMG]
[/url] Nürburgring Nordschleife by 
Kyoto - Gion_3 by NismoR33, on Flickr[/IMG][/IMG]eople/nismor33/]NismoR33[/url], on Flickr[/IMG]
