First, it would have to be a spun microglass filter, anyone who thinks micron ratings hold up with paper filters I have some great swamp land to sell you that will make you a million dollars, and you will be the one to buy it, and give me a cash tip for doing so. Then you want to look at Flow, entry holes and cheese grater design really allows for good flow. Then, you might want a thick loose media that will flow great and hold contamination. The only one I know that does all of that is Royal Purple. You do give up stuff like everything else, for that great flow and thick loose media you do leave a bit of micron rating on the table, so there is an argument for something being better. Plus, you may want a higher psi bypass rating. So if you consider all of that, pick a spun microglass that suits you better if you are looking for other features over what RP has to offer. Wix XP tighter thinner media maybe give a better micron rating at first, some guys prefer that, spring bypass as well, doubles the psi to bypass, someone might prefer that as well. But for me it is RP, I put another brand also spun microglass and the truck had a warm idle tick, too restrictive. That was the old puro synthetic, don't know about the new one.