It strikes me that even though the M20 seems by the specs to be way faster than anything out there, there are quite a few who have the same impression as you Jake. Considering that Marstom has quite a bit of experience from A-cat sailing, one would expect the M20 to have a fast hull design. Being 30 kg lighter than the Eagle 20 should also give it an advantage. Still, you are not the first one, Jake, to be somewhat disappointed by its actual performance.
All though maybe not possible to sustain over a longer distance, 30 knots in a 20' cat is quite impressive!