You're quite fearless in modification from stock...I'm envious! That should help make for big, fast/strong groove vortices inside the manifold, and big gains in efficiency.
Duralube will help the surfaces stay slippery, but the RVS rebuilds them, returning them to factory tolerances, or tighter. I'm obviously a big believer, based on trying it in my last vehicle, and don't hesitate to suggest it based on that.