ok, you have found the leak.
i still do not understand why you are considering an EGR valve that does not fit your engine?
if you are buying a new one just get the right one.
personally i would try used for a few bucks.
somebody is bound to have one somewhere sitting around.
especially if it is not an exact match.
my guess is that the same year EGR valve from a different model subaru will be an exact match.
suabru does not like to use different parts on different cars, in the same years.
it can happen, but usually only in ''transition'' years, like 1999.