BD-Power Duramax Exhaust Manifold

Hey, back to the original question...I literally live right across the street from the main BD shop in Abbotsford, and I talk with the guys pretty often. The stock exhaust manifold has a "notch" in it, reason being the DMAX was actually designed to fit into the old, box style body, and the steering column was in the way, but that's not the case now because of the changed body style. The BD exhaust manifold is straight through, no notch. The stock manifold on the driver's side only flows about 80% of the exhaust that the passenger side does. Simply put, GM hasn't changed the mold for the one manifold since the DMAX was first manufactured. You can get more info on the BD website at Diesel Performance | BD Power