FreeBSD Gateway

[Victor Foulk]

Hello all,

I have been looking into setting up a network gateway
using a FreeBSD box, so that I may employ many of the
network security features of the system (and to 
overcome the fact that the current network is
insecurely connected to a much larger ~public LAN).

The configuration would be much like this:
{Internet}--{Huge/NastyLAN}--{FreeBSDGate}--{SafeLAN}

Most of what I see states that I should use 
a *minimum* of:

266Mhz processor
64MB RAM
1GB HD (actually ~2GB based on number 
        desired security apps)
2 Compatible NIC's

What I really had hoped to find, was more of an experienced
networking guru's thumb rule equating the number of safeLAN
workstations with the required gateway RAM/Processor; to 
enable all safeLAN users to experience a minimal network
transaction time roughly equivalent to what they would see
if plugged directly into a really good hub.
Something maybe in the form of:
Proc Speed = X*Users+Y
RAM = W*Users+Z

I am far too new at this to have a clue what numbers to use
to even approximate. Any advice on this matter would be most
appreciated.
Thanks!
Victor