In 2002, Fr. Bernward Deneke, FSSP, a gifted musician, celebrated a Requiem Mass in Poznań, Poland, for the soul of composer W. A. Mozart, and Mozart's own setting for the Mass - Requiem Mass in D minor (K. 626) - was played.
Gloria TV has a recording of the event, for your meditation this weekend:
Unfortunately, this is not such a common occurrence: Mozart's Requiem being used for its real purpose, as musical setting for a Mass according to the Traditional Roman Missal. Fortunately for anyone who will be in or near New York next Wednesday, it will be possible to be present in a Holy Mass in which the piece will be in its intended place and occasion, a Church and during a Mass for the Dead. The Mass will be celebrated in the Church of St. Agnes, on November 6, at 6:30 PM.
(We have received news of other such Masses on All Souls' Day, at Holy Rosary, in Indianapolis; and at the Assumption Grotto, in Michigan.)