Re: How did the Borg get to earth, before they got Transwarp?
The Borg had transwarp at least ten years prior to Q Who, according to Voyager. Dark Fontier establishes this.
But even if we don't want to accept this, presumably they could have used one of those subspace corridor thingies from Descent. After all, it transported the Enterprise and Lore's Borg ship to the Delta Quadrant and back again.
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