I've pretty much decided to buy a big battery mod. I really like the Provari with 2year warranty. Is there any reason NOT to get one of these (other than the expense of it)? I know it's big and heavy...but it also has the meters built in, a nice long warranty, and can be dialed up or down to use with almost anything right? I'm thinking I'll like it better with a couple of the shorter 18490 IMR batteries but I'll probably go ahead and get at least one of the 18650s and cap too. OK, lets say I get this Provari...I think a backup of some kind would be a good idea in case it has to be sent in for repairs or gets 'lost/stolen'. Thing is, I don't want to have to get more batteries and chargers of different sizes. Is there a less expensive NON-VV mod that takes the same 18490 IMR battery as a Provari? If there aren't any other 18490 mods out there...could I get a RoughStack Maxi (or some other 18xxx0 mod) and use an 18490 IMR with some kind of spacer in it, or would it HAVE to be the 18650 size? Provided it's safe/possible...Would the IMR type battery work at 3.7v in a non regulated mod like the RoughStack, or would it be a higher voltage? Thanks much!