If you're going to be transferring it from one machine to another with WGet and they're both on professionally hosted lines (IE a non DSL/Cable line) then it should be fine to just forget tarring it, as it's text it'll transfer pretty fast on it's own and would take about the same time, but it may affect yoru bandwith quota on either host; so tarring would be best if possible.
And we're looking at a 200mb dump being 20mb.