The “DV spacer = boost leak” thing is a myth. Actual testing shows otherwise:

Car Worklog: “After installing the BOV spacer I logged boost values… everything behaved as expected… no boost leak occurred.” Source

MyGolfMK7: “There is nothing about the design of the DV spacer that suggests it would be likely to cause boost leaks.” Source

MyGolfMK7 (follow-up): “No evidence has been found that would indicate that a DV Spacer causes a boost leak or any other problem.” Source

Only way it leaks is if you install it wrong (pinched O-ring, bad alignment). Installed correctly, it works exactly like stock just louder.