So I've searched for info on air filters and have come across some interesting thoughts. I have always been under the impression that aftermarket air filters such as K&N and True Flow were the way to go. But several posts have got me wondering about their effectiveness. So I guess what I am after, is it a good idea to put a reusable filter in my 4Runner (of which I own 2, an 08 and 97) or should I stick with the basic paper? What filter should I use? I searched for a True Flow for my 97 but no one has them. Please help. My objective is to help my fuel economy. Air movement is key, and I know it won't be a huge increase, but every little bit helps.