RE: TF FW190 GIANT ARF
Why not build a box and slap some shotgun buckshot or BB's in it with epoxy? Some simple walmart BB's are what I use. The cool thing about this method is that, no one knows that's a weight and the box becomes usable space.[8D]
Here is a pic of one I did for one of the Doras. Just over the muffler it can be seen.