I lost you. Diesels don't have any manifold vacuum, since they always run wide open throttle (i.e. no throttle plate). While in boost, it seems both a gas or diesel intake manifold would act the same. I think the only seals are between the oil-filled bearings and each manifold side. Might be other differences with a diesel though. The oil sure gets blacker and worse. The 300D engine is 3.0L vs my slant's 3.7L, but the slant can rev higher so the turbo might be slightly undersized. The inlet doesn't look small though and looks like a standard Garrett turbo.
