Hmm.. I guess it depends on your undersuit plans. From the pictures I've seen Halo 4 MC has the chest pretty tight around the pecs, but it is totally your call. If anything it would be nice to have a little more room to move your arms. But, you have to keep in mind though the other pieces of armor, like when you are wearing a helmet and the chest is bigger are you going to be able to turn your head?