MacPro 5.1 & high capacity hard drives

I've run out of internal storage on my MacPro 5.1. And although I have a 24 bay NAS in the background, I need more high speed storage.

I would think my cheapest option would be to upgrade to larger disks, as I currently run 4x2TB in Raid0.

Does anyone have experience running larger disk, such as 4x6TB in Raid0 on a Mac Pro 5.1?