Personally I would not consider buying a vehicle private with a lien unless the holder would turn title into my name upon full payment - phone Wescom credit union to check their policy.
Sure you can surf the Internet all you want for answers and advice, to me the buttom line is, when you buy private you're at risk with any transaction.
There is a million cars out there,,, sometime a deal may seem to good,,, and a another pigeon is born.