My (postfix) mail server currently runs on an old PowerEdge 2650 and it badly needs a hardware upgrade.

I would like to put it on an 8 core (3rd Gen) 2950, but have no idea how to go about changing hardware. Do I have to install CentOS on the new machine and then figure out how to get postfix/mailman/ldap all working on the new one? Is there any type of information on how to do this? I have no idea how modular linux ACTUALLY is. If I install a new version of CentOS 5.4, should I technically be able to copy over /var /usr /root /home /etc and have the server work exactly the same but on the new hardware? Or would I need to recompile certain programs? I feel like I never learned these type of things anywhere.

Or what if I ran clonezilla on the server and tried to restore it to the new hardware? Would I need to recompile/update the kernel? 

Thanks for any help/input/direction.