to make the itr manifold fit a gsr head, you'll need

itr head or b16a head.

b16a head = itr head with port and polish.

i've heard of people cutting and welding to make it work,

just sell the itr manifold, and get a skunk2, it's better anyways (larger plenum) 64 on the skank2 VS the 62 on ITR manifold.