Guys 07 vrs BLT engine code 60k miles

Has whats seems an exhaust blow when cold from engine bay area as engine seems much louder than it used to be.

Car has full Milltek system and my mate whos an audi master tech cannot see any soot anywhere and even pressurising sustem by using a rag it cannot be found.

Only thing he noticed was the usual oil weep from the boost pipes and wonders if its a boost leak when cold giving a louder induction noise that i think is the exhaust.

Anyone else had this ?

Egr valve in good condition?

good idea as this is closed whilst cold, but ive fitted the smaller gasket to reduce the flow.

Might be worth a quick look over bolts etc to make sure they're still tight..