You should be ok with the upgrade, but it might clobber your kde menus, and a few apps might disappear. It's a good idea to keep the installers for non-urpmi stuff in a directory you can go through when you get a new system.
what non-rpm apps do you have? If you add the plf and texstar sources, you can get most anything through urpmi, from mozilla firebird and realplayer and flash to freecraft and sqlite and mplayer-codecs and dcgui. Even kdevelop3/gideon alpha's are around somewhere. I'd look into it.