Cool! Have you ever studied the manuscript to see how much of it Mozart actually wrote? Only movement fully orchestrated by Mozart was the first movement, the Introitus. He got about halfway (Hostias/Quam Olim) with only vocal parts, figured bass, and suggestions of first violin figurations. I love it, but prefer to call it the Mozart/Süssmayr Requiem! Highly influenced by Michael Haydn's Requiem, and that one and even Salieri's are worth a listen. Start here:
I like Costas Court Composer; he basically writes Haydn symphonies that sound like Haydn, middlin' Haydn anyway. Nice guy, and when I asked if he were Joseph Haydn, or Michael, in a past life, he thought it was pretty funny...