I don't do much playing on anything other than a Bb, but a good friend has asked me to do the Bach Kantate Nr. 51 with her in the fall. The copy of the sheet music I have is for trumpet in C. I do not own a C trumpet, but I do have a 1950's Benge D/Eb trumpet. Would it be sacreligious to transpose the C part and play it on the D trumpet? Anyone?