I've checked this with both a 3rd party mod and the latest BTCC Toyota Corolla. In VR (Rift CV1), toggling the Mirrors key only affects the virtual mirrors - not the in-car side/centre mirror. I.E. you cannot turn the in-car mirrors off to save FPS. On the 3rd or so keystroke, the mirrors briefly flicker but then instantly reappear.
the cv1 perform very well, if you have problems with them bad business, because even with a gtx 1070 they go very well, from there upwards left over
I’m getting on fine with the CV1 and 2080Ti… …but it *could* be better and it’s so far unclear as to why you can turn off mirrors in monitor-land but not in VR…
Same problem with drivers labels. It sounds VR means no toggle, that's all. However toggle works with 2d tv view while in pit at least for labels but it's not really useful.
with a 1080 ti in the cv1 I maintain a fixed 90 fps without problems... the mirrors of the formula pro if they are deactivated in vr I have no problem there...