All v2 versions (if new use latest).
Personally i am not experienced in the import piece, so can not add to significant issues/troubles or good working ( not much replies and comments throughout). Do keep in mind that importers normally ONLY do parts, not everything...(like users /forum etc..)
As for : account ?? This is standalone software. there is no account needed.
Only if you want something that is not supplied with the 'pack' like a certain theme (layout) or a plugin that does something.
Think of it more like : hey i need 'customized' things than you 'go' and request/post for such. Those needs (time and work) than will probably ásk'for some fee. Although easier things are also often archived, or by contribution offered free. (of course one can not speak for a designer or developer; they have to want to do it..but that is business) a lot can be achieved.. or get familiar with things and 'do it yourself' ( as many do; and that is one of the strengths of the software..). (and of course the base of opensource).