The Motherboard manufacturer is normally the best place to get drivers. If they are showing Windows 8 drivers, I would probably use those.
Going to a site like Intel for specific drivers might get you a more recent version and probably be fine, but that would be your choice.
Bios updates may help a particular problem. If you system has a way to recover from a bad bios flash, you would be OK, but most folks say if eveything is working, maybe a bios update is not necessary.
I update mine all the time, but I am familiar with the recovery process if something goes wrong.