i personally would e-file the amended return as you can now do this for federal personal returns. When you enter into turbotax your amended return it should confirm if you can e-file (I'm not 100%sure since you mailed your original return.) If for some reason it gives you an error, then print and mail again.
(Recommend and urge you to do the following) I personally print and keep a paper copy of my return only with data needed for filing, but I also keep a PDF copy of all three separate files (return only, key calculations, and all calculations) this way if something happens to my original ttax file format I can always view a pdf. its also very simple to keep for review to gather the required info for next years e-file or file just in case ttax doesn't have it for some reason. This may seem like overkill to you, but it only takes a few minutes and saves much time and stress if it's needed-not to mention the pdf really take up minimal space and the printed copy is just a few pages depending on complexity of your return.
