I've just discovered this incredible work, and I'm surprised it hasn't been recorded more.
Honestly, if historians suddenly discovered that Mozart actually lived to 1793, and that he wrote another Requiem in 1792, and this was it, I would have believed it.
Just between last night and this morning I've been listening to this recording on Youtube: http://www.amazon.com/Michael-Haydn-...I2RP1P9CA04C0O
I will be purchasing this recording as soon as I verify that I can afford it (I've spent over $200 this month on music CDs/DVDs).
Here is the first part on Youtube: http://www.youtube.com/watch?v=ADYNeuS8P0k