yes they have online servers, but you can also race it on your computer alone
heres the biggest r-factor site, that has all the newest mods for different types of racing
http://www.rfactorcentral.com/
the actual r-factor site is
http://www.rfactor.net/
i run the dirtfactor mod which currently is a beta demo version
http://dirtfactor.net/
the guys at har racing are pretty good at painting custom dirt cars for other people
http://www.harracing.net
some of them also are painters on the dirtfactor site as well
this is no playstation game, its a simulator so all real world physics and adjustability come into play(downforce, spring rates, shock dampening and all the fine tune details), you could spend forever tuning these cars, but there is setups you can download that take out most of the work for you
there are also great mods like the nascar mod by vhr
http://www.sunriseautodetail.com/VHR-STO...20News.htm
they are finishing up the details on the new craftsman truck series as well
guys like dale jr, aj almendinger and many others are actual racers in the online leagues