the way to tel is like CRXLVR saiod, the stamp which is in front of the engine right before where it bolts to the tranny there will be a like 2"x2" square with the letters HM i think and then B18C1 or B18C5.
the GSR intake manifold starts from the head and rises up and then falls in the back, the ITR manifold comes straight outta the head and looks like the LS manifold. then theres the valvecover.. and about the tranny code I dot know those.