In build 118 the 60's mod the car mirrors are blank, I have to use the virtual mirrors. Also when I first installed rFactor2 and started putting in mods I had no engine sounds, figured it out by trial and error by moving the sound files into the proper folder.
Mirrors in the 60's mod have been blank since B85. As for the no engine sounds you shouldn't have to move files/folders around to get it to work. The RFMOD files are packaged in a way that their contents get installed to the places they need to. In theory this should stop people messing things up, just stick the RFMOD/RFCMP in the packages folder and install it. Where have you installed the game, which files/folders did you move and from where to where, like a lot of posts its short on detail, people often seem a bit vague on what they've done and even when you do get details they often appear to make no sense. Of course ISI haven't helped matters by having specified 2 install directories, forum's full of posts from people who've managed to screw that up somehow. Also allowing the ModMgr.exe to be run directly from the 'Core' folder, these 2 things are probably responsible for half the problems people post about.
That sound bug is one that has afflicted a few people, and no explanation has been forthcoming. I have had it on every build and I followed install instructions to the letter. The OP will have solved it by merging the sound folder from his documents folder to the core folder, at least that is what I and others have done.