If it helps at all, there is barely any weight difference between the MX and hifi. Personally, lighter is nice, but not always better. There gets to be a point where its too light and not enough material. My most important point by far, these are suggestions. As a shop worker, my most important bit of advise is to go in to your local shop and try the shit on! You dont need to buy there, but you need to find a snug yeet comfy size, and you just have to see what fits best with your head. Helmets arent all the same shape inside, so try on stuff first.
~MidwesT AlliancE~
RIP RICK JAMES