good buy! amazing race sim.
for general info, mod info, tech support and such look here
http://forum.rscnet.org/forumdisplay.php?f=916
no cars yet i'm afraid, might be quite a while until we see any, not aware of any current projects, thats not saying there isnt any though, but there are plenty tracks. infact i think malc30 posted up a very convenient track pack in another thread i'll see if i can find it.
yes here
http://forums.overclockers.co.uk/showpost.php?p=6549968&postcount=60
gives you all the essential tracks for online play.
**edit for above**i'm running 1280x960, DX9 shaders, full ingame graphics settings, FSAA level1, no Vsync, track characters off, not sure but think thats everything covered.
it never drops below acceptable performance usualy up 60-70fps+
night time with full grid and headlights(most stressful time) on sometimes dips to the mid20's on the starting grid but quickly climbs as the field spread out.
looking at your spec you should have no problems at all playing the game in its full glory.