Looks might be deceiving. The accuracy might well be off, overly simplistic, and parts are likely to have been modeled wrong. I would be super sceptical before even concidering buying anything.
I suppose any 3D application with a polygon smoothing tool would suffice.
Personally, I find the lack of proper references a big problem when modeling. I modeled the Millennium Falcon basicly by comparing the model with screenshots from the movies
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