KDE 3.0 -3.?

Hi,
ive just got the gentoo 1.4 UT cd and im wondering about the best way to 
upgrade my current 1.2 system.
presently, i'm running a very plain 1.2 system with KDE 3.0, and the main 
reason i got the 1.4 cd was to uipgrade kde to a more recent version

so my question is, should i uninstall KDE 3.0 (or any other packages i want to 
upgrade) before i install a new version or should I simply "emerge -u 
package"?

also am i correct in assuming i can just mount the cd to 
/usr/portage/distfiles to emerge packages from the cd?

	Kind Regards,

James Ferguson