Noob alert!

I run a RHEL4 server (32 bit) with Plesk 9 installed. This has been a continual upgrade from Plesk 8.2.1. Because RHEL 4 ships with PHP4, I needed to use ART PHP 5 packages, which have been installed (and updated) since using Plesk versions 8.2.1 through 9.
However, a recent update to Plesk 9 includes "PHP 4 configurator". Issuing up2date -u --dry-run gives me this:
Testing package set / solving RPM inter-dependencies...
########################################
RPM package conflict error. The message was:
Test install failed because of package conflicts:
file /usr/bin/php-cgi conflicts between attempted installs of psa-php4-cgi-4.3.10-2 and php-cli-5.2.9-2.el4.art
I've been reading other posts on this forum and the advice generally seems to be "install the ART update first, then Plesk". Would you agree that this is the best thing to do in this case?
I suppose I am trying to avoid any major compatibility issues which would inevitably mean working a weekend to resolve (and potentially upsetting hosting clients).
Thanks,
j