use evod head-no need to, dont change the stem, the evod as is will be fine. also if your into re-wicking your own coils 3.5mm wick when wet will tighten up the draw. i found it works real good if your mod has a top ring with no air flow channels. my old epic storm works really well with the protank. also another option is a 510-ego adapter and use the beauty ring that came with the tank.