Here is an offcenter view showing the portal to the flapper. The right side has been cut back as far I dare to avoid thinness; the transition is smoother than stock.

I also raised the roof. And I did it so as to allow more bypass flow. That is why the roof is not a smooth oval shape.

When the wastegate is closed, the exhaust can go to the turbine wheel as it did, only better: the compression of the exhaust gases will occur closer to the turbine wheel, not back inside the manifold.

Perhaps a better way of saying it is that the exhaust gases will now get squeezed together right there in the turbine housing scroll, just before it hits the wheel. I had modified the manifold outlet to direct the gases from each runner to aim for the middle of the scroll, instead of at the far side of the turbine housing.

Also; when the wastegate opens now, the bypass flow will be better.