On the X-ray, watch any of the joints, every where they are not a ball joint they tend to be a little tight and may need to be drilled slightly larger. The thigh pieces specifically are known to be an extremely tight fit. You can probably force them in, but the mushroom peg will twist off. The part that the peg attaches to can be widened by filing the top of the inside area. I have heard that there is an issue with Air Burst in Combined mode where his combiner port won't disengage from Fierce attack after put together. I may have just missed it but has anyone heard how to adjust the connectors so that they don't get stuck?