I personally don't race online anymore, mainly because I no longer have the time to dedicate to it. So I just play offline for fun.
I've only tried ACC on PC in VR and while it works well, the graphics aren't optimized for VR; it just doesn't look polished like GT. But otherwise once you get used to the slight difference in graphics, it's truly a game changer. So much so that I feel bad for those people who bought triple screens
I don't play iracing personally, not sure if it supports VR. I'm really hoping AC2 supports VR and that Sony releases their PSVR2 drivers for PC around the same time. Ohh baby, I can't wait for that, plus the modding community support?!?! My odds on GOTY (with some assumputions about VR, naturally).
I have the DOF Reality P3 platform, its the model 'meant for showrooms with heavy use'. I figured, in for a penny, in for a pound. It comes with all you need, except the seat itself. I bought the GT Omega RS 6 seat and some Soporoco seat belt on Amazon. That isn't really necessary per se, but I'd recommend it for all the reasons you can think of (immersion, safety, etc.). All in on that front, with shipping to the USA and I'm just under $4,500USD IIRC.
Don't forget, to play GT7 with a motion sim, you'll need a middleman app thats running the Sim Race Studio app. Licensing there is pretty cheap (to start with) and I think their Raspberry Pi magic box is like $200USD? Or you can install the app on a laptop/pc to have running alongside your PS and PC. HTH!
Jerome