OT: New MailScanner machine

[Ken Goods]

I'm putting together a new machine to replace the one currently filtering
our mail and delivering to an exchange server. The load increased back in
December due to an update of MailScanner, Spamassassin, ClamAV, (and adding
bitdefender). Spamassassin is timing out regularly and the machine is in
heavy swap. (P233 with 196MB, processing ~8k emails per day).

I have found another machine in the boneyard that has a little more
horsepower (550 PIII with 384MB) and would like to build a new box running
the same configuration, plus it gives me a chance to add some "legs" to the
old OS (Redhat 9). My plan is Centos 4.0 for the OS and sticking with
everything else as it suits my comfort level.

My question is this... I want to load the least services to support
MailScanner, Spamassassin, Clam, Bitdefender, Webmin, and Mailscanner-Mrtg.
I noticed that there are three ISO's for Centos and another for Centos
Server. Can I get away with just the Server ISO and use a minimal install or
do I need to get all four and use a combination of them? Sorry if this is
noob but I've looked around and can't find much information on the
difference between the server ISO and the others and thought someone here
may have some experience.

Any help would be appreciated much.

TIA
Ken