I never own Human Alliance Soundwave before, because it's very expensive, and the leg's design looks pretty bad for my taste, doesn't seem worth the high price tag.
Recently, I bought a KO Human Alliance Soundwave, then I finally have a chance to play with it. My feeling is that the upper body is perfect, but the legs are so week, like spider or something...can barely stand. (In fact, when I took this picture, I need to lean Soundwave against the wall. )
Also, Soundwave is significantly shorter than other Human Alliance toys.
So I studied it for a while, found a very simple and near perfect solution to improve using a leg add-on kit which anyone can easily built, let me show you here.
After this leg add-on DIY, Soundwave is slightly higher than other Human Alliance members, and that fits the image of DOTM movie.
