Unboxed the Caelus. Wow, they lightened up things. Less carbon cloth in the nose, and less glass cloth in the tail of the fuse. Thinner sheeting on the wings, and appears to have less internal support out past the wing tube. I'd venture the first version was a little over- built, and Top Model pulled out everything possible to lower the final weight. Imo, they should have left the nose carbon cloth in, that continued to the landing gear block. Might not be an issue for those, like me, that will use the rear motor mount plate that Mike sells. The mount will add strength and twist resistance to the fuselage. I may add some carbon cloth strips where the motor mount is epoxied to the fuse. A point of reference....my version 1 came in at 4950 grams with no real effort to drop weight other than the carbon prop and spinner.