I actually had a conversation with a vapor shark rep regarding the comparability of the dna 30 and the kanger subtank nano. They told me to upgrade to the 40w but at a substantially higher price. This kind of makes me a bit leery when it comes to putting any money into a vapor shark.
Isticks makes an awesome 50 watt box I've seen it is cheapest $36 on some sites
Love my iStick 50