(1) Bios update is normally only required if you are having a problem. If Not having a problem it is not recommended to upgrade the bios.
If you buy a MB that has been on the market for at least 3 to 4 monthes, it will probable have a stable Bios. Say the bios revision is only one later than what is on the MB, then read what it improves on, if it does not apply - don't update. Primarily a bios update is needed if you upgrade to a newer CPU and or memory that was not orginally supported. Should not be a problem with a new Sandbridge Build.
(2) Updating the Bios is not really difficualt. Usally there are 3 methods (A) From within the Bios itself (Safest and the recommended way). (B) By booting the Computer to Dos and (C) from within windows. The Only caution is to NOT power off the computer while the update is in progress. You down load the new bios, stick it on the USB stick (May need to format the thumbdrive as ntsf). Boot the computer and select the key to enter the bios update screen, then tell it to upgrade - usally well stated in the MB manual (Just a matter of following the prompts).
(3) As to newer drivers. Again you only HAVE to do this if experiencing a problem. But again it is not that difficault. You can generally find what a new driver updated and see if you need. Unless I have read that a newer driver than what is on the disk IS NEEDED, then I just use the driver disk supplied. NOTE: This applies to a "Store Bought" computer the same as a "Home Built" system.
Added:
While I was typing I see that MISRy poped in. Only thing is I do NOT recommend doing the Bios update from within windows. This method has cause problems in the past, altho it has improved - it does carry more risk than doing it from the Bios itself.
It also made me think of a Caution. Never update the Bios untill you are sure the "newly" built system is stable. But this should be donebefore installing the Windows operating system even if you do NOT update the Bios .
From a bootable CD run memtest86 for a Min of four hours to verify that the system is stable.
Link:
http://www.memtest86.com/download.html