In case anyone's interested, I got my Hot Toys TrueType Slim body today and started swapping out my broken RAH body. The body itself is brilliant, really good, and not just for armored figures. With regards to swapping the RAH body there are some issues:
-Head: Swaps easily, just unscrew the neck post and pop onto the HT body.
-Hands: Big issue. the RAH hand posts are way too big for the HT forearms. I ended up enlarging the hole on one hand, which didn't work so good, and just cutting down the post on the other, which worked better.
-Feet: Wider than the RAH feet. I cut the boot open at the back and inserted the foot that way.
-Waist: Bigger than the RAH. Trimming the inside of the cod piece definitely helped, but I had to slice it to get it on, and then glue it together again. The belt with the pouches also needs cutting. I just put mine on with a gap at the back, but I guess you can put a rubber band at the back.
After all that, it does look quite nice, but I'm not rushing to replace my Jango bldy just yet.