I would be tempted to purchase, and renovate in the US. Then ferry the completed project over. There are some super deals going at the moment, and shops are plentiful, although type dependent, you would require to do some homework. My own view, and please it is my personal view, is that Europe, and the EU registry is too restrictive, and expensive, to undertake the purchase, and then renovation. Trust me, been there and done it.
Hone in on your type requirement, spend an evening on sites with planes to sell, then begin to make choices. It is an ABC, process, but the U.S. is pretty vast, with some good refurbished airframes, going at good rates.