1999 Fazer 600 surging power

[Lawrence]

I had a cheap Hi-Flo filter that i felt wasn't letting enough air through.
And it wasn't until i replaced it for a K&N that i realised how ill fitting it was too in comparison.
It rattled about by a good 5mm whereas the K&N was a very snug fit.

What symptoms did you get?  I have one of those filters but have always had a hesitation when opening it up.