Well, I have to disagree about saying that a plane is TOO heavy at anything under 11 pounds. It just depends. Although light is good and most times better its not always better. You judge a plane by how it performs, not how much it weighs. I would take a plane that performed perfectly at exactly 5kg's over a plane that flew ALMOST as well at a lesser weight. Furthermore if flew perfectly at 5kg's on the money but I had room to shave weight,, I might do it, but not at the expense of structural or componant intergrity. Shaving weight just so I can say I have a 9-10 plane would be silly.