I dont have any comments on the manifold, but if your looking to lower egts, you might want to consider a ppe boost controler or a kennedy diesel boost stick to raise the boost levels. i ran a boost stick for a while i got an average 150* drop in egts while running a edge stacked with a predator programer. The added timing of the programer also helped lower egts also.
What kind of egts are you seeing?
What kind of egts are you seeing?