I have a gsr bottom end being built by a buddy of mine, and he called today and asked about missing an oil cooler...He said it looked like someone bypassed it or something about making it like a b16. I told him i wasnt sure since my friend i got the block from died during the summer. He said that he has always seen gsr's and itr's with oil coolers. I know my LS didnt have one and i dont remember seeing it on a few of my friends b16s and gsr's. I just wanted to know if it is manditory that you have one?