which are better or are they all the same and would one head on the other block make a difference in cr?
1991 Skyline GTR
1996 Sunfire

Same difference. Not until 98 did the 2.2 head and cam change, and you don't want to go mixing 97 and earlier with 98+, not without some severe modification.
Heads and blocks are interchangeable between 95 and 97, but I want to say you can't use a 95 cam in a 97 (I don't think it has the timing notch).
fortune cookie say: better a delay than a disaster
95 cam doesn't have the cam postion sensor lobe on it thats the only difference in them the rest of the specs are the same
JBO since July 30, 2001