Good info about the battery relocation. I was thinking of doing the same thing to my '71. I have a 1980 and a 1982 Spider that has the battery in the trunk - same location as yours.
FYI, the 1980 and 1982 don't drive like the '71. Nor do they have the same "cool factor". Chrome bumpers, cool interior, carbs vs SPICA or Bosch!
I think you'll have no problem getting your asking price for the car. Gorgeous body, fun to drive, responsive, open air, mechanical feel, the right color (red), great condition and Webers! For a modest amount of money, your '71 Alfa will make someone really happy.