Not much more to add, but chiming in with a hearty "seconded". It's much safer to have your own separate "application" perl (which can be owned by a non-privileged user if you so desire) and don't touch the OS' copy.

You'll be more than glad you took the 15-20 minutes it takes to build /usr/local/perl-5.10.0 when you realize after updating things that the package manager would have rolled you back to Foo-0.31 despite your having upgraded to Foo-0.42 and you've saved at least that much time not having to diagnose that (to say nothing of the next n times something similar is going to happen; or of the flexibility you get by being able to move to 5.10.1 6 months before your OS finally gets 5.8.9).