Looking at the NACRA archives it shows both boats with a 31 foot 7 inch mast, both weighing 420 pounds. Sail area 251 square feet for the 6.0 and 264 aquare feet for the 6.0 NA. According to the brochures, 6.0 NA has a larger main than the 6.0 and also a larger jib with new bow foil.