Those figures quoted by Terrafugia are patently ludicrous but in any case the basic issue is the stipulation of WEIGHT as some sort of valid criteria for how much you can penalize an aircraft compared to another one (via excessive certification procedures) --weight is NOT a criteria for setting 'standards' for any experimental aircraft and neither is it used to categorize cars in terms of what engineering justification is needed and finally it has next to nothing to do with actual flight safety or any other related matter. Wingloading (in take off or landing configuration -ie near to the ground) IS a meaningful quantity but more than that is actual minimum useable speed --in the case of Terrafugia they got a little too clever and deliberately set things up so that their ACTUAL minimum useable speed on take off was over 80 MPH even though the nominal stall speed was conforming to LSA --defeating the idea of docile near ground characteristics (the Slovak Aeromobil has a 90 MPH take off speed for much the same reason - to do with weight distribution on the wheels ) The pilot is not aware of the WEIGHT of the aircraft he is flying and it is not a primary factor in anything of significance --certainly not to the level of a hundred pounds or several provided the real factors that matter like wing and span loading,inertias etc are the same . Making anything out of all carbon fibre and not trying to save weight by external bracing for example,using three wheels or using any high lift devices,etc already forgoes any claim to have cost or 'best efforts' in mind and deserving some bending of the rules --they ignored advice freely given to them before going ahead along a path to predictable failure. What IS the LEGAL basis for specifying WEIGHT as the criteria for treating one aircraft differently than another ? ( I had to look into this in regard to the same issue in Australian certification exemption weight limits [the 'under 400 lb AUW' ultralight class of ANO 95.10] -it turned out that there WAS NO legal basis for it --aircraft could only be categorized by FUNCTION ,not weight,colour,national origin or any other irrelevant factor --the regulations were admitted to be invalid and they had to be rewritten (a process still going on many years later ) Bad engineering and conception cannot be attributed to some arbitrary legislation either.