Cadillac, Buick Top J.D. Power Customer Service Index By Jason Siu Apr 09 2014 Share this Article Tweet Two American automakers have topped the J.D. Power U.S. Customer Service Index (CSI) Study for the first time. Continue Reading... Filed under: American Buick Cadillac Featured Articles Luxury CarsTags: Buick, Cadillac, consumer satisfaction with dealer service, csi, csi study, customer service index, j.d power