Felix,
You guessed it. I don't want to upset any particular fan clubs but lets just say that the filters are going back into the air tubes. (pipercross)
Bizzarrely the thing was running very lean up to half revs then a little lean from there on up. You would think that any problem with a lack of airflow would cause it to run rich?
Maybe Junking the mesh on the air intakes has leaned things off but I would have thought that removing an obvious restriction in the intake was a good thing IF you can keep the fueling right.
I don't think there is a lot to be done to adjust the fueling with the OEM open pipe ECU.
Maybe a power commander to richen things up is needed?
Looks likes its Bye bye to 50 plus MPG in cruise mode??
Ray