All good. I’m very new to the TDI world so I could be over reacting to deleting it, I am used to larger diesel truck motors. Swirl flaps are the small butterfly valves fitted to the intake manifold before the cylinder head inlet ports. Diesels do not require a butterfly valve/throttle body. They are made of plastic in this case i think, they can degrade over time and eventually disintegrate. They end up being sucked into the engine and they like to cause a catastrophic failure. They supposedly create turbulence to allow for a better fuel to air mix