Try these links and click on 2006, 2005, and 2002 for the Forrester. The click on the reliability tab. The engines have problems until 2006; the explanations are given. The same seems to hold for the Outback (click on 2007 and 2004, then reliability tab).
http://www.autos.msn.com/research/vip/default.aspx?make=Subaru&model=Forester#used
http://autos.msn.com/research/vip/default.aspx?make=Subaru&model=Outback#used