which would you replace first?

My father is looking to improove his Vinyl set-up which consists of Soutmaster (STOCK) a Benz MC cart (the $600 model...red "ACE"?) and a Musical Surroundings Phonomena stage with Kimber Hero cables. Between the stage and cart what would give most bang for the buck in the $1500 price range if we only want to replce 1 of the 2 at this time. Thanks as always...............HAPPY NEW YEAR