Props for doing this! It's cool to keep track of the winners, and to see all the themes in one place.
Btw, you said in the start of the post that you'll update every two weeks, and in the end that you'll update every week. Not that it's a huge deal or something, just pointed it out.
Hey. Yeah, lfs-db went down quite some time ago, but a new one was made: http://www.lfsdatabase.eu/. And I think another database is being built right now. The design dudes' site was pretty much dead for a long time and then it disappeared. C40S has released few skins here resently, however.
The Castrol Celica has been done many times, but since it looks like you're doing good job, keep on going! One suggestion thou: make the green darker. You might also consider using one of squale's RB4 kits, they add a lot of great detail to the RB without looking fake. downloads here
Sorry, probably don't have time for that. In the next two-three weeks I'll be home for about 3 days, and those are pretty much occupied. After that my army service starts, so that's a good bye to skinning for who knows how long.. Anyway I'm not that good with coming up with my own designs, most of my skins have been replicas.