The total volume of the V2 (two slots) is greater than the volume of the V1, so the V2 should allow for greater airflow. I only have the V2 mini, but a V1 Nano, and same coil, same juice, the V2 is like breathing... almost zero restriction, as compared to the V1 Nano, which has some restriction (and an airy-whistle)... sorry, but that's the best comparison I can make between the V1 and V2 bases