Trevor, hi.
It appears there are two programs called 'Bluetooth Explorer'. One made by Apple, which is part of the Xcode toolkit. And the above-mentioned one that is made by a private developer and is available in the Appstore.
I've got the feeling you are looking for the Apple made one, since that does give you information about the BluetoothAudioAgent. (something the Appstore one doesn't do) This program used to be installed as part of the Xcode toolset. But is now made available separately in a bundle called 'Hardware IO Tools for Xcode' (can be downloaded from the Apple developers webpage --you'll need a (free) developer account)
Now, that being said, you will indeed be able to change the audio bitrate with it. But Bluetooth Explorer does not give one too many options, for more improvemtents you will need to edit the plist: ~/Library/Preferences/com.apple.BluetoothAudioAgent.plist
The Bluetooth Explorer is however very good for debugging the edits you made to this file.
For some good starters on editing said file, settings that on my system provide excellent audio quality (much better than default), i'd refer you to this webpage: http://mariusvw.com/2011/06/16/how-to-fix-the-crackling-bad-sound-of-bluetooth-a 2dp-headsets-or-speakers-on-mac-os-x/
Best of luck! Greets,
Jesse