Sorry I didnt read your post closely enough piston PIN remover, so not sure if any of these help but you may be able to rent them from an autoparts store too.
http://buy1.snapon.com/catalog/item....&group_ID=1594
also these tools are listed for a 2004 impreza procedure so the parts department at the dealership should be able to say whether they would work on the svx. Or someone else on this site but I figured I would post it for ya
ST 499097700 PISTON PIN REMOVER
ST 499897200. PISTON CIRCLIP PLIER
and this thread had alot of info in it that may help I don't know for sure though.
http://forums.nasioc.com/forums/arch.../t-313637.html
This site looks very informative for special tools for all subaru's including SVX and some tools are also listed for Legacy as well.
http://subaru.spx.com/index.asp