[mtfeeney = Baron]

The vision enhancement and audio enhancement don't list a max rating.  Is it just as much as you can squeeze into any gear you can find?

[Palladion]

On SR5 444, you are absolutely correct, it does not look like there is an upper limit on visual enhancements, except by Availability, Capacity, or nuyen.  Probably supposed to be Rating 3, but something to post in the errata forum.  Audio enhancements are Rating 1 to 3 on the table SR5 445.  As for the ones in cyberware, they are limited to Rating 3 maximum by the tables, SR5 454.