My piece has an 18mm female and usually, I use an Alex K bushing diffy to 14mm. I was thinking of getting a new downstem and ashcatcher and am unsure as to what size joints to choose. Would there be a noteable difference in airflow with 18 > 18mm (18mm male on the a/c) as opposed to 18 > 14mm (bushing style with 14mm male on the a/c)? Or, would I still gain that airflow on an 18 > 18mm with an adapter (so a/c would still be 14mm) as opposed to the bushing type? Thank you for any help!