wotcha and welcome - as with most Japanese cars a well maintained scooby can run for many years with no trouble, there are some issues with recent legacy diesels, allegedly due to misaligned gearboxes on assembly. There have also been some engine failures with the 2008 - 2010 2.5l sti engines (ringland failure) caused by sustained high rev running on the standard maps. Motors that have been remapped to 330bhp had the different parameters added to stop the lean running at high revs. Petes mate also had a failure due to low oil levels
pros - great handling and fun to drive with addictive turbo rush - cons frequent visits to garage and tyre supplier :)
we have a buying guide here
http://uk.subaruownersclub.com/forums/topic/1619-help-check-guide-buying-1st-subaru/