I just finished watching the latest episode of engine masters on motor trend. For once it was really useful infor for fieros and general mechanic stuff rather than just big cube v8 stuff.
They tested a whole slew of oil filters for flow numbers and construction on their dyno. As is no surprise, the WIX filters were two of the top three for performance. But the top was quite a surprise! The flow numbers for the WIX, WIX Race, and K&N gold were all pretty much the same, but the microns of filtration were very different. The WIX Race was a 61 micron filter for thicker oils, so if running straight weight 50 or more it would be a great choice. The WIX standard was flowing about the same but with a 20 micron filter for lighter oils (5W30, etc.). The K&N gold however was built with a heavier housing and had a 10 micron filter with no noticable depletion in flow rate. So ya, the WIX we all have been loving is a great filter, but the K&N gold filters smaller particles and does so without losing any noticable flow.
Food for thought on your next oil change.