ElFroggio
Just do a regular full backup to play safe.
Do not rely on your memory of installed contribs, use
/sbin/e-smith/audittools/newrpms
The investigate each contrib if compatible with sme8, refer to links on the same page you were looking at.
Then uninstall the php5 contrib, although if I recall correctly, the sme8 installer does remove this.
I tested an older awstats contrib on the weekend on sme8.0 final and it works fine so I expect the current versions work too.
If in doubt test first on a test machine.
The upgrade should go smoothly, just follow instructions carefully.
If you have a 2 disk RAID1 array, you could remove one drive as a a precaution, and if the upgrade goes bad, you can easily revert to the removed disk still with your full current sme7 install. Then find out what went wrong and try again.
If you really want to be careful, then remove a drive from your live server (assuming 2 disk RAID1), and try the upgrade on another test machine with only the one drive inserted. If all goes well great, proceed to updating the live server. Better to be safe than sorry.