A while back engine masters did an episode on oil filters, They tested Wix,Fram,K&N and a few others. K&N gold was the best for flow and particulate filtration. I would have liked to see a test using different weight oils and also test the Royal Purple filter(have read good things about it). If flow is your main concern a remote duel filter is what you want. As mentioned flow is limited to the diameter of the threaded nipple. I also assume you are using a high output pump(these where tested also). Another trick is to use a thicker spring or a washer to bring up the psi output of a pump.