Shame it's not Game Stock Car Extreme, at this point I can't justify buying rFactor2 given the state it appears to be in.
Having said that I'll probably get it at some point anyway, I would like to race a BTCC car in some sim. Probably wouldn't be able to race with you chaps as last time I tried with iRacing it was super late for me in the UK.
Allegedly you can fix it by using a mod called "OneTweak" after installing Skyrim Script Extender (SKSE) - I think all it does is run it in a borderless windowed mode. Seems to be a common problem on Windows 8. You'll have to have a look into installing those two, they are easily found.