I saw in this months Hot Rod mag that they did a filter comparison on five filters. They were AFE, K&N, Rush, Holley and a paper Purolator, the filters were a 14" x 3" style filter. They tested airflow, power and compared price. They had two different dyno tests, one was on an engine dyno and one they had a chassis dyno. The AFE flowed the most air and the Purolator the least. I believe the air flow went in this order, AFE, Holley, K&N, Rush and Purolator. All hi-flow filters made about the same hp, the Rush filter made by Barry Grant (Demon carbs & Nitrous works) actually made the most tq, about 3-4 more than the next closest.
The Purolator filter made about 3-4 less hp and tq on one dyno but made the same hp on the other dyno with still about 3-4 less tq. The Rush filter only outflowed the Purolator filter but made the most hp & tq which is interesting. The AFE was also the most $$, $58, the rest hi-flows are about $45. I may try a Rush filter if I can find a retailer, there aren't that many I can find. Just thought I would pass the info on.
Jim