Ok im going to put on the perrin equal length hearder on my car and i have a 06 wrx and i have bin looking all over the place for this oil cooler. Now for this header to work to my understanding is that i have to put a differnt oil cooler on from a 02-05 wrx. Were the hell is this thing? Is it what the oil filter screws on to? And has anyone did this with out changeing the oil cooler? If anyone can help that would be great !!!