They share almost nothing, the 1990 had all new sheetmetal, a larger engine, 1.6 vs either 1.7 (GS-R) or 1.8 (all the others). They really didn't look the same either, the 1990 was larger, and the foor door version was a sedan (the earlier models were all hatchbacks). See below for details. http://en.wikipedia.org/wiki/Acura_IntegraI doubt if parts for a 1990 will fit the 89, if they did the supplier would certainly list it, they would not want to turn away potential customers. Partstrain has plenty of stuff listed for an 89:http://www2.partstrain.com/v5/produc...7164&Nty=1Good luck.