EGR????

Is the EGR a supposed improvement to the engine operation or a requirement to meet exhaust emission standards?

exhaust emission improvement, specifically the reduction of oxides of nitrogen.

when it all works properly you dont know its there, when they go wrong you notice it, removing it allegedly improves engine performance but really its just restoring what was lost.

check and flush the intercooler and inlet manifold while you have it out and apart.