Client storage of field material and products

I have a long term client for whom I would like to provide long term storage of old shows and field material. Many of these projects were originally shot on Beta SP (little field material would be preserved of those shows). For current projects, they have gone tapeless. They have many of the old field tapes at their facility. I keep some of them in my studio for source material. I have also transferred to the digital domain much of that old material. The new material (tapeless) resides on my hard drives. This makes me nervous.

I would like to buy a hard drive that would contain all their vital material which would be kept at their facility. I called G-Tech and was told that their G Speed Q line would meet my needs. I have looked at the price breakout of this line and note that the 4TB Raid array setup goes for $799.99. I also note that the 'spare drive' category has a 3 TB drive for $499.99 (a price that is more in line with my thoughts).

I have two questions -

1.) Is the G Speed Q line a good choice or are there better alternatives?

2.) Could I legitimately use the 3 TB drive for this long term storage even though it might not have the Raid capability?

Thanks for your thoughts on this matter.