I've heard about skins. Is there a site anywhere within LFS where you can see them "on display" or is one just reduced to seeing one flash past you on the straight and think, "cor, if my car looked like that I might go a bit faster!"

Err, there's a few here you can look through.
http://www.lfsforum.net/forumdisplay.php?f=29

If they are skins you've seen online, you can always check them out in LFS or the CMX viewer - just copy the skin to the appropriate folder. Don't use them online without the author's permission, though.