I'm specifically thinking about the Arrow III. There are hundreds or possibly thousands of turbo Arrow III's, but almost no non-turbos.
Could I buy an Arrow III Turbo (PA-28R-201T) that is at TBO and just put in a non turbo engine? Would it then become a PA-28-201? Can you do that to any aircraft that has a non turbo version as well? For instance, could you convert an Cirrus SR22T to an SR22?