05 Scion tC here with F90BT unit. Think I am running the 3.3 BT software, but since I just updated the firmware to 3.0, BT has not been working right and now not showing the version number anymore. Going to re-run the 3.3 update and see if that helps.
For microphone, I mounted it to hang down from the driver's side visor, virtually in front of my face while I am driving. Amazingly it seems to make a difference just between being held between visor and ceiling and just hanging down off the visor so assuming mic is omnidirectional. And I would consider Scion tC's pretty quiet compare to some other cars. One of the lowest interior noise ratings in it's category.
You might want to play around with mic location. Getting it up to the visor is pretty easy on the Scion actually. You can feed it up behind glove compartment and/or peel back the front pillar covers without even needing to remove them.
Enjoy!
Clif