I have a 1998 E320 with 111k miles on it. I've just replaced all 12 spark plugs and the original Mercedes air filter to K&N air filter. I do notice the difference when using the original Mercedes air filter, the engine seems like wanting more air, but not able to. With K&N, it seems more air flow to the engine. I do pray that it will not bust my air sensor.

 

I hope you are not pulling my leg, because I am been told with different stories about how good the K&N air filter performs. I have placed back the original and thanks for the link.

 

I've got my refund yesterday on K&N air filter. The manager was asking me why for returning it and I showed him my iPhone with ISO 5011 test report and he was speechless... Thanks!