I made the mistake of trying to remove and swap some parts between Snake and Kinnikuman when I first got them. Not recommended. The new joints have a small mushroom peg on each end, making them almost impossible to remove. Only thing I don't like about the Minis, you can't do silly part swaps like with the larger Revoltech figures.
That sucks, I'm going to get a replacement. I think no matter the joint tightness, I'll just stick with it.