Well, the clarity of Mozart's mind is heightened by the precise nature of many early music performances. Recently ran across a Nimbus CD of the Hanover Band/Goodman doing his most popular items: the g-minor symphony (#40), Eine Kleine Nachtmusik, and the Clarinet Concerto. Nothing special in this -- except the clarinetist is playing a "Basset Clarinet;" with a lower range than the modern instrument and sounding very, very smooth.
This used purchase set me back the handsome sum of fifty cents and has become my goto selection for the clarinet concerto -- one of those works you definitely should take with you to a desert island.