The weight is higher than stock but the power is much higher as well. 18.5 ounces and 430 watts is 380 watts per pound
The issue here is CG location. I had to add 1/4 ounce to the nose to get to balance at 107mm per the manual. This resulted in a tailslide and flip over. Fluttered like a leaf. So I fixed it and added .5 ounce more then flew again, this was still too far back, fle about 150 feet out then nosed up and I gave full down and then it went into a perfect flat spin. So I have it fixed again and am trying even more forward CG. I need to get an incidence meter on this thing, it looks like the tail has a ton of incidence built in it but it may an illusion due to the dihedral.