Hey guys, I'm new to this vaping stuff and have a few questions regarding this setup. I'm planning on getting this starter kit (Joyetech eGo-C Twist - Kanger ProTank Series II Starter Kit - Vaporfusion) but I after doing a bit of research, I want to know whether or not these two pieces of hardware are good for each other. It says on the site that the Protank II has a resistance of 2.5ohm, but I wasn't too sure what the voltage settings on the ego twist would be at. And would the voltage setting lower the battery life or damage the battery at all? Also, I've read that people buy additional coils, why is that? Thanks.