>>6914469>>6914529>if there is some difference between the mk 3 and 4, i haven't been able to find it>The chest is different and so is the legs and bicep areaThe suits are almost entirely different. In fact, the only thing I see that's the same between the two is perhaps the feet. Everything else is so different. The proportions are much better on the Mk.4, everything is much more angular than the soft, rounded Mk.3, and this isn't even taking into account the triangular arc reactor he installs toward the end of the film.