Ruf RWD street car is a terrible car, unsaveable at anything more than tiny slip angles, feels like a piece of shit compared to any of the AC cars. If this is what a 911 road car feels like, I'll take the Cayman.
I do really like the track car though, the highest compliment I can give it is it feels like AC with slightly less grip. The default setup isn't great at all, but with it sorted its a fun car, plenty of traction, can happily catch it on acceleration out of corners at quite high slip angles and I can almost feel the tyre actually biting and gripping the road instead of floating on top of it.
It is undeniable that iRacing runs great and looks very decent, even at 5760 res with high details and plenty of AA/AF I'm still getting a solid 124fps and silky smooth gameplay, while with AC on my own I'm struggling to get 100 unless I turn everything off, including most AA and AF. I'm very happy that iRacing have given me something to play with and properly race again while waiting for AC to mature.