I would just like to ask. If I replaced libraries of the KDE desktop with libraries from QT 5, in order to completely integrate QT into the system, much like Windows or OSX. I have a general idea of what I'm looking for, but I haven't been able to work out the details. Is there anyone who might be able to help.

At the moment, KDE is undergoing a porting process in certain parts of itself to Qt 5. This effort concerns kdelibs primarily at the moment, and comes under the name "KDE Frameworks" (which will be kdelibs for Qt 5 as such).

At this time, no other parts of KDE can be compiled or used against Qt 5, and as such any such upgrade or replacement would break your KDE installation completely.