I recommend Berstein version for Requiem which I think it is quite
outstanding, both on interpretation and sound effect.  It was recorded
in a church (sorry I forget the name) which can definitly guarantee a good
sound effect.  Berstein recorded this work to memorize his passed-away
wife Felicia who died over ten years ago.  He obviously involved personal
feeling in the music interpretation which makes this works very solemn,
magnificent and sacred, not completely Mozart ever lasting style.

This is such a famous version and it won't be difficult to find it.

Ying Liu