It's basically the same car mechanically but in '98, the car was re-named S/V 70 and had undergone many body and interior changes all with new parts. Like most car companies, Volvo used parts suppliers who probably offered parts prices less expensive than others and obviously those weren't wise choices as many of those parts didn't hold up well and thus probably cost Volvo more in losses than expected, not to mention losing disgruntled customers who traded out of them for another brand of car altogether.
Penny wise, dollar stupid IMO.