For the front I first cut the stock coils, then new Carquest, then used Hotchkis. Nothing looked and/or felt right. For the rear Intrax was the first try = redonkulously low. Those went onto my son's '88 MCSS. I settled on tried and true sacked out old SS coils all around. 5# in the Airlift bladders. Bilsteins. Heaven.
http://www.impalassforum.com/vBulletin/showpost.php?p=2157958&postcount=24
http://www.impalassforum.com/vBulletin/showpost.php?p=2157958&postcount=24