Got a small for my boyfriend it runs very oversized I would size down

Im 6’1, 180 lbs, and usually a medium in Y3 but once in awhile something comes through thats at least 2 sizes too large, even for an oversized fit. Insanely nice quality and great for layering, but I exchanged for an XS. Wish adidas had specific measurements for its Y3 line as its a tossup between getting something meant for the japanese market (runs smaller than normal mediums) versus something massive like this one