as for the ccv mod, if the pipe is vented to ground, can the rocker cover still breath? if theres no suction on it?

Diesels don't have any suction in the inlet manifold, it's forced pressure induction. The PCV is actually pushed out by lower end pressure blow-by. Just make sure the mod hose doesn't have any kinks or blockages, or you will blow oil seals.

As for EGR delete, mixed results. Cleaner intake manifold, no hesitation, but increased cylinder temperatures at steady cruise and idle. This could possibly lead to early valve seat wear. Also NoX is extremely poisonous, so it's not an environmentally friendly mod.

I've ran both mods for about 17k with zero problems other than a bit of a oily vapour smell in the cabin at idle as I made my own catch can can and is not the best. I need one of these bad boys with 19mm pipes Saikou Michi