Your results bring to mind a question I had. Even if you increase the ability of a car to inhale more air, will it do it if the restrictive point in the system is the exhaust? I recently put a K&N on my 740iL and likewise did not see a difference. I would think if you considered the intake and exhaust as a single system, airflow through the "system" would depend on the most restrictive point in the system.

I would think that the real test would be if you know for certain that the air intake is the point of restriction, then you could test the "system" with the standard filter versus the K&N. I am planning to replace my exhaust with a free-flow unit in the near future and may run a similar test since I kept my old air filter. Am I missing something in this logic?