I have an Asrock 990FX extreme3, you only need to update the BIOS if you're running windows 8 (I had to, but windows 7 was fully supported when I installed mine). They don't recommend updating to the newest BIOS if you're running windows 7. The same is true of the 970 series. When you boot it up, check to make sure your BIOS is v1.6 if you're running win7 you're good. If you intend to run win8, you can go to Asrock's website (www.asrock.com) and update to the newest version. You won't have to install a different CPU as the compatability is the same, the instructions are just different for the OS, and you can run win7 without an update, it will just run less favorably.
Here is the BIOS update link to download the newest drivers...http://www.asrock.com/mb/download.asp?Model=970%20Extreme3&o=BIOS
I would go with the extreme3 by the way, the extreme4 has had some QC issues in the past, and I wouldn't recommend buying it.