[suicideneil]

Well, concidering the Erevo will use the same tranny, and same diffs (internals) as the emaxx 3905, then your choice of esc and motor should be identical to that which you would choose for the emaxx, which makes life easier. if you go for the MMM esc, it would probably be worth going the whole hog and running 2x 3s lipos, though 2x 2s will be just as good with the correct motor. Size wise, 8000mah 2s lipos will fit, or 5000mah 3s lipos- unsure of the manufacturer, but Im guessing those are maxamps lipos that Traxxas tested with.

That pretty much tells you what size/capacity lipos to run, though there are plenty of other makes and brands, just be aware of the dimensions.