To my original question - does anyone know (or can find out) whether the 1990s BMW or Miata mirror base covers the holes and sits at approximately the right "angle" to look correct? I posted the dimensions of the Z3 ones as 2-3/8" x 4-1/2" overall and I just don't have access to a flag mirror right now (or car) to compare. Step 1 is whether the oval of the BMW mirror is big enough and step 2 is whether the mirror would sit properly to look "correct". From looking at the shape of the door I would think it would.
Thanks,
Ron