I am picking up a G-Raid GR42000 (2 tb version) external hard drive, and for the life of me I cant find if I can swap out the internal drives for 2tb drives (4tb total). I know there are some limitations with the hardware on some drives, but there is a 4tb version (GR4 4000) which is essentially the same drive, but comes with 2-2tb drives. Are there any issues with swapping out the internal drives? 2tbs are great, but I will be raiding them, so 2tb raided would be nice for speed and redundancy. thanks!