your working with 2-different mpem connections.  The spx, if anything like my 97, is in the grey box, with wires prtruding from it.  The mpem you got now (97gtx), all wires go to 3-big plugs, that connect "to" the mpem.  Unless you spend the time, figuring what color wires go to each gauge...fuel/oil,...etc, then i would nt worry.