The key takeaway: all of the parts have serial numbers that are paired together, so if you replace any of the components, even with other genuine Apple ones taken from another identical iPhone, you'll lose some or all of the following functionality, depending on exactly which components they were: True Tone, Auto Brightness, Battery Health, FaceID, Portrait Mode, and Cinematic Mode. And while they claim it's for security that they disable FaceID, the rest are all completely indefensible.