well, i read many times that S200 is the ingoing group of WRC. And i dont think they are made from "old wrc cars" - atleast i cant think of any. There is this Fiat punto, VW polo, some toyota, dacia logan, skoda also developing s2000 car....
i just checked the WRC 2005 calendar, and every rallye was ~350km - and im sure there is some request of minimal length being somewhere around it. Ok, sure its nothing compared with 8000km, but watching that would be even more boring. as for myself, i LOVE rallying, but couldnt care less about dakar - its too long, boring stages, and not enough action
and about the mechanical diffs etc - i think the group S2000 which is curently being developed (and is supposed to replace WRC group at some point) has that.
i guess i might have the same problem as you - and ive noticed this only since ive had new gfx card - nvidia 7600GT (before that i had radeon 9800)
it looks like there was no AA and the whole "flickering" of the armco is annoying (mainly noticeable on the armco along pit road on the left). But the AA is actually at 8x and AF 16x
change resolution in LFS, set graphics details to max, in your graphics card drivers set AA and AF to maximum, use polygonal lasso tool to separate the sky,trees etc from the foreground,...