Apply some oil on the blackboost pipe so it slides in easier into the oem rubber coupler. Don't tighten it yet as u might need to make small adjustments when filters go on Be careful of the passanger side, I did not remove the oem coupler as I couldn't figure out how to remove the oem plastic vent hose, so I did it while it was on the car. Again with some oil on the coupler it slides in over the blackboost pipe without issue.