If this were me, I'd do a parallel install in /usr/local, mv /usr/bin/perl /usr/bin/perl-orig, ln -s /usr/local/bin/perl /usr/bin/perl, and see if I break anything. Just compile from source so you can control where the install is jailed.
And, obviously, don't upgrade in the middle of a production cycle! Sorry, forgot to mention that before. Unless you have an incredibly compelling reason to upgrade, wait until you can afford to screw something up.
