I may be wrong but if you backup up before you would not be able to restore nor would they work. At least that was the deal when I rooted. That means that you will lose the data (call log, text message). Not a problem for me. Once you root make a backup of the OS and the apps then install/flash a new rom.
That's what I tried. There is a section in the registration where you have to put some kind of a puzzle together and its acting up on my phone for some reason. Its all good though, I'm probably going to root my phone on Sunday with a buddy who wants to root his HTC Evo.