I recently found out that my microphone is unavailable for any app exept for the dialer most of the time the phone runs. So I can take calls all the time but Google and S Voice tell me they can't use the microphone.
I'm still in contact with Samsung support to find out whether it's a hardware or software issue, but I can't say that for sure for the next two weeks at least.

I am not sure if this has anything to do with the crash issue because it seems like it depends on permissions on my own TS³ server, but I thought it's worth mentioning it.