Use the following command in the terminal to see values for lame encoder
gst-inspect-0.10 lame
I've added a bitrate parm in addition to lowering the vbr-quality to 0 from 6 for best quality
My Preferred format setings:
audio/x-raw-int,rate=44100,channels=2 ! lame name=enc mode=0 bitrate=256 vbr-quality=0 ! id3v2mux