Yes all the mods have made it smoother. mpg is the same but it idles and accelerates much better.
I think the fibreglass delaminated as the glass was wound in a spiral if that makes sense. The crack I guess opening as the car vibrated & heated up.
I await my brass 10-12-10 T piece coming from china to complete the rebuild. I don't trust the plastic equal T which is 12-12-12 but the hose from the breather is 10 mm.