Sophos vFW VPN - Users

Hi all,

I was considering purchasing a virtual firewall, but I have a doubt to clear up.
The vFW will mainly be used only to create a site to site where there will be about 100 users behind it. (There will be no local users on the LAN instead)

In this case, how do I identify the correct firewall type? (2C4, 4C6,,etc) (I only have Throughput as a parameter for VPNs)
Are users behind the VPN counted as if they were normal users?

Thank you!

..::Hertz::.