Welcome to BWL, Dwarvenbeer!
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I understand that I have to create a new game in order to take advantage of most of version 3.0's features
Not most of the mod's features, but yes, a minority of them require starting a new game if you didn't already have IA v2.0.
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Could i start a new game and import my pre Improved anvil saves into that new game, and continue from there?
What was the version of Improved Anvil you had? Could you please explain in more details how you intend to import your saved game into a new game?