Thanks David, I thought I heard somewhere that the Borla manifold is a copy of the Hall manifold but has a built in vacuum plenum. Does that sound right? From their website:
"Cast in A356 alloy and machined in precision CNC equipment the manifold has cast-in plenum facilities for the MAP sensor and the Idle Air Control"
Are the Hall manifolds still being produced or are they selling old stock? The pictures on the Borla website and the Inglese website look to be the same manifold.