Poor performance top end

[Sidewaysbmw389]

Recently fitted a m52b30 to my car .its got M50 manifold, and schrick cams .Whilst at a track day a couple of friends commented my car sounded flat pulling out of a corners .a mate was also there ,he has a m52b28 in his .they said his sounded crisper and revved quicker .is this just the way a b30 is or could it be a Vanos problem .thanks