TKlingman welcome to aximsite
You have to purchase the wm5 CD if you want to try it. As w3iner said if your pda isn't broke why fix it. I would suggest that you stay with wm2003se. If you have the wm5 upgrade cd and still have a dell warranty then you may want to see if you can convince dell to upgrade you to an x50v. See this link to see how others were able to get dell to upgrade.
http://www.aximsite.com/boards/showt...ll+upgrade+x50