Charger, Nitecore or Xtar. Both have fans. Get one with 4 bays, even though you're looking at a 2 battery mod. Believe me, down the road you'll kick yourself for only getting a 2 battery charger.
The Alien is a great kit. Well performing and pretty popular around here. The BB is a great cloud machine but only 2 ml which will disappear quickly. There have been some who report paint issues, but mine looks fine, and lots of reports from others that it's holding up just fine. However, it's an issue to be aware of.
For a second tank to play with, I like a Tobeco Super tank. Inexpensive and takes any Atlantis style coil. that means lots of choices from different manufacturers, so you're not as limited in coil selection as say the BB is.
As for batteries, any of the 20A offerings from LG, Samsung, or Sony should be fine. Buy only from a reliable dealer such as Iuum or IMR, as counterfeit rewraps are common on eBay and even Amazon (through third party sellers). Here's a useful list of recommended batteries from Mooch, our battery expert.
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