I recommend that you use the latest SVN builds for PCSX2, they fix a lot of things that PCSX2 officially has problems with, and there have been a few fixes for Ico during the time between the official release and the SVN release as well.
Sure, if you really want/"need" the highest quality there is you can grab remuxes. But will be pretty big file sizes, so disks can be better in that regard.
But piracy is free so...
some bluray rips are kinda crappy, remuxes are a more safe bet, but i usually don't have trouble finding a good rip, there are certain groups to avoid and some to look out for