You need the A2DP support package in the A2DP thread. That configures MPlayer to connect to your headset in lieu of using the speakers. You may also find the updated BlueZ packages to be of use or, alternatively, lardman's dsp-sbc (I don't know which is better: ARM opts or utilization of the DSP?)
I'm not maacruz, but what's a forum without discussion?
To me, my N800 isn't "faster" but it's certainly a lot more responsive, making it faster in that respect. For example, I'd sometimes tap the screen when it was blank and it would take ~5 seconds to wake up. Now, with Diablo-Turbo, it wakes up pretty much instantly.
Same. While maacruz's mini-rc/sysvinit packages and the newer kernel have reduced the chances of my N800 hanging upon shutdown, it does still happen.