Marstrøm themselves list the M-20 weighting 115kg's (dont know how current that number is). With the modifications Hakan mention, the boat measured at Texel could easily have gained 10kgs.
Actually I don't believe Hakans modifications can account for 10 kg weight difference.
Hakan names
* stainless steel rigging instead of carbon
* mainsheet system with blocks at the end of the boom instead of a cascade system.
* snuffer instead of a snail.
* Mainsail weight, could easily be 2-3 kg extra here, depending on type of cloth and battens.
Stainless steel rigging weights 2.5 kg or less in total. Carbon rigging something between 0.5 and 0.7 kg
Mainsheet system weights 1.5 kg in total when using a lightweight sheet line like swiftcord. Cascaded system shall not be lighter than 0.5 - 0.75 kg
Snuffer ring and sock are lighter than the Marstrom snail.
Mainsails are surprisingly invariant in weight, this is mainly due to the fact that the reinforcements along the sides account for most of the weight together with the battens. My mainsail is only 8 kg in total, I suspect that the M20 mainsail is only 10 kg in total. saving 2 to 4 kg on a total weight like that is no small modification ! You just don't safe 20%-40 % on an item like that. But even if we could than we'll would end up at (2.5 - 0.5) + (1.5 - 0.5) + (0) + 3 = 6 kg weight difference in the worst case scenaario.
Personally I'm convinced that they are producing the boat heavier, i.e. the hulls etc.
But moreso :
Marstrøm themselves list the M-20 weighting 115kg's
With marstrom I have learned to ask :"is that including or excluding the sails ?"
Wouter