I have both the ARF and the kit version and I had to add no weight to either one to get them to balance. The ARF has a GMS 76 engine on it and the battery is under the fuel tank up aginst the fire wall. The kit built plane has a Magnun 91 4 stroke on it and the battery is back aginst the rear wing mount bulkhead. Both planes fly great and I love flying them. The GMS engine is the best running 2 stroke engine that I have ever had. It ran perfect right out of the box and only needed minor tuning. It gives the 4* unlimited vertical performance. The magnum also flies the 4* really good and it sounds so sweet. The vertical performance is not as good as the GMS but it still hauls the plane vertical pretty good. It will not hurt to have to add a little weight it will still fly great.

Rick