It is easier using USB to install in UEFI mode. Not all CD/DVD drives will boot in UEFI mode and therefore they don't give the needed UEFI option in the boot menu.
Use a tool named Rufus to prepare your USB flash drive using the Windows 8.1.iso
I don't recommend using RAID on your boot drive, but yes create the RAID first and then make sure the BIOS is configured for UEFI. You should not need any additional drivers.
Once you have prepared the USB flash drive, boot the machine and press F8 and then in the boot menu select 'UEFI:Name of flash drive' to boot in UEFI mode ready for installation of Windows. If Windows complains that it cannot be installed on your drive, it is because you have not formatted the drive using GPT. Hit F10 and use diskpart to convert the drive to GPT.