Would also go with the Subox mini kit. Got both and both work very well. Am a Tootle Puffer that prefers cooler vapor and can achieve it with the SubTank mini.
I have used my rebuilt ProTank 2 coils (30 Kanthal, cellu cotton, 1.5-2.0 ohms). Also have used the Aspire "Replacement" BVC's 1.8 ohms (NON Nautilus). No modding necessary with either these coils.
Have rebuilt the OCC coils that come with the Subtank, but do horizontal coils 'cause I'm incapable of building a vertical. You also have the RBA to work on.
I love that you can replace the battery on the Subox, plus there are inexpensive "skins" available in 6 different colors. As a "girl" I enjoy matching outfits. Oh, and I use much longer, narrower bored tips. Helps cool down the vapor.
You can use the SubTank mini on the Cool Fire IV if you chose to get one later during a great sale! I just think you have more options with the Subox kit. Good luck in whatever you decide.
