This is a cool DIY Bluetooth mod that looks like it gives you good results for a small investment in parts.

“Why did I do it?
Well, the original BT headset was kind of crappy. People were complaining that they can’t hear me properly, and the audio volume was not the best either. Plus, wearing it behind the ear is not very comfortable, at least not for me.
Another reason is that I like to hack things, just for the fun of it.
I want to mention that this is a prototype, so it’s not looking as good as it could. I use it only at home, so the aesthetic aspect was totally unimportant for me. All I cared about was for it to be comfortable and reliable.”