The new BME 115. Tons of power and lighter than the 85. A little more money but you won't be needing to step up in engines if you go to a heavier airframe.

DA is a good choice as well but why settle for less than you could have? If going with the DA 100 you'd be spending the same money for less engine, more weight, and less power. If the 85 it would be less money, more weight, and less power. With a 3w 80 and would be more weight, less money, less power. With the 3w 100 or 106 it would be the same money, more weight, and less power.