Hi First of all thank you for reading this message, I know this forum must get a lot of requests for advice so I appreciate any replies. I am currently in the process of switching over to digital formats for all my music and films etc and need a storage solution for this. I was therefore thinking about purchasing a NAS. I also would like to stream movies etc from the NAS to my TV and music from my NAS through my streaming music player (Bluesound Node 2). I have not delved into 4K as of yet but this is probably something that will happen in the future. I am interested in the Synology DS716+ and was looking at the 2 x 4TB (8TB) loaded DS716+ initially but had a question I was hoping someone with more experience could help with... Is there a difference in terms of performance between a DS716+ with greater amounts of storage e.g. the 12TB or 16TB unit and a DS716+ with 8TB storage attached to a Synology expansion unit DX513. I understand that if I got the 8TB unit initially I could then only have 5 x 4TB units in the DX513 (unless I bought all new bigger drives), and therefore one of the differences would be storage, is that correct? But is there any other disadvantage to it, does adding the DX513 reduce performance in any way, or is it just simply an expansion pack that has no impact on performace? Is there infact an advantage in that I'd then be able to use other RAID options with having more than 2 drives? I'm thinking in terms of having the DX716+ 8TB initially to get me going and if/when my storage needs increase I could add on more with the DX513 rather than buying a very large DS716+ unit now. Or even at the point where i do need more storage, sell my DS716+ and upgrade to something presumably new and better in the future that synology will release. General thoughts on the use of NAS vs. any other storage solutions? Would it also be advisable to back up everything elsewhere than just on the NAS? e.g. an external HDD? Thank you so much again. Michael.