Hi,
I heard, that MDK offers KDE rpm's for paying clients only. But perhaps that's wrong...
Well updating a rpm Distro with tarballs is not very easy. At first you have to install the development version of many Programs like X. Then you have to get the QT 3.2.2 Version and compile it. Take a close look at the readme files and be sure that you enable everything you need. Then you have to download the source from kde.org. I think they have a little howto.
But be aware, that compiling kde from source will take at least 8 to 10 hours... (well only if you run through without any errors)
Another way ist to wait until MDK releases 9.2 in a couple of weeks.
Dim