I think the OEM filter would be fine, it's a compromise of flow and efficiency. I don't have a GTR, I have an affinity for GTR's I would very much like to have one one day. I have been around quite a few pretty quick cars. There are GTR's VR38's that make tremendous power 2000+hp, they make pass after pass. I know the levels of build, bottom end block work, so on. With any build though, you have to be reasonable with the driving procedure. Heck, when it's cold I take it easy on everything I have.There is a guy on the gtr r35 page that has built motor from same place and uses wix 57202 instead of the 51060 racing filter. He said he has close to 15k miles without any problems from using that filter. What’s your opinion on that? And a lot of guys that track the gtr use oem filter with 15w50