Speaker works okay, can't hear a noticeable difference. Flash works (both bright light and "red" video recording). Also tested: Buttons, headphone jack, front camera (using "Simple Mirror" from Store).

I called somebody today and they said that they understand me now clearer than before (but that might be because my original old housing / microphone had some problems since the beginning). Also, my old housing was squeaking a bit when you squeezed it on the lower left edge, this is gone with the new one (but again, it seems like my original housing was a bit bad in general).

In general, I'm quite happy with it so far. I noticed a small dent at the back near the silver camera thingie, but not sure if it came like that or if I did this. It's nothing functional, just a cosmetic thingie, and not really noticeable until you look really closely.