How many computers and other attachments do you have in your LAN?
How big is the hard drive on your current main computer? and how much memeory?
These are the main issues that will come into play. V6 is only slightly more of a memory hog than V5, but about the same. If you are going to go paperless you have to be sure of your backup systems.
You can search server and review long discussions about servers vs peer to peer. It would be worth reviewing these
