Many parts should be salvaged from dead VWs to save money and because some parts can't be found after market.
New banjo fittings like those on the left aren't cheap. They can often be salvaged from gas VWs and other diesels.
The fixtures bolted to the head in the pictures on the right were salvaged off a gas rabbit and have an extra 5/8" output hose. It's better than cutting into the heater hose.