issues with upgrading to firefox-1.5 on FC4?

[Robert P. J. Day]

i'd like to try out some of the features of firefox-1.5, but trying to update
to that version on my (fully-updated FC4) system out of the FC4 devel repo
shows a sizable number of other packages that need to be updated (not
that big of a surprise), and finally fails with a few missing dependencies
(allegedly, xorg-x11-devel, XFree86-devel and others).

is it safe to try to update to firefox-1.5 on an FC4 system and, if so, what's
the proper incantation?  do i need any of the other repos enabled as well?
i'd like to keep this as simple as possible.

rday