This is a link from someone who make a pretty good document of their 06 USDM SPEC B converting over to a JDM SPEC B front bumper.
Its REV A-C so usdm 05-07 legacy.
http://www.nonox-design.com/projects/project_LegacySpecB/
He did not use the JDM Bumper Beam, fender liners, undertray, and foglights.