What will happen is if you do buy a SATA RAID controller card is you'll get a second BIOS menu that you can get into to configure the raid for the drives on that controller card.
Definitly do some research because there are some cheap RAID controller cards that no one should buy and some expensive ones that make people scratch their heads and wonder how they're in business.
It shouldn't touch your intel raid at all.
Thanks for the insight. Been away from building PCs for quite a few years and am catching up on things. Was thinking about just getting an enclosure for the drive, but will check also into the SATA controller card.
And just to be sure there won't be any conflict with the onboard SATA and the Intel RAID setup there?