Another question occurs to me...
If I have an NPC hacker that decides to data spike the samurai's cybereyes, how is the device rating of cyberware determined? I know there are different levels of cybereyes but that isn't really meant to be the device rating, is it?
Rating is not the same thing as Device Rating.
It's left to GM fiat to assign Device Ratings to most devices. My recommendation is to continue to use 5th edition's yardstick for Device Ratings:
DR 1: cheap, expendable goods (cans of soda, clothes from a vending machine, etc)
DR 2: standard consumer goods and standard grade cyberware
DR 3: security/police grade hardware and alphaware
DR 4: military grade items and betaware
DR 5: cutting edge devices and deltaware