The Torqeedo does have some more motor noise-so it is more than just wake, water splash--more of high to mid pitched whine.
We found Max speed with the older 1103 to be 2.5 knots with my Caracal 18--both heavier and longer LWL than 16' C Dory. I would expect somewhere in the 3 knot speed for a 16. The problem is the range. With the 16 certainly 5 to 8 miles would be do-able. At slower speed (2 knots) then the range would more than double. A 3.5 hp Merc 2 stroke, will give slightly more speed and of Course almost unlimited range on any of these boats--with the lowest pitch prop available. The newer 1103, has a bit more power and larger batteries, so it might go slightly faster, and with maybe a mile or so more range.