I just got some Bosch microedge wiper blades. Should I just replace the rubber part of the wipers(actual rubber wiper blade) or install the whole new wiper (including metal and rubber) from the bosch kit I just got?

 

The whole new wiper.

It ought to clip on easily and take only a few seconds to change.

 

If you have the whole bosch assembly, then i would replace the whole thing to see how you like it.