Money Porsche tops list of car brands with highest customer satisfaction; Fiat ranks worst March 14, 2019March 14, 2019Douglas A. McIntyre, 24/7 Wall StreetComments Off on Porsche tops list of car brands with highest customer satisfaction; Fiat ranks worst The J.D. Power 2019 Customer Service Index study showed how service can be either improved or undermined by how well dealers handle owners.