well i looked further into this and i have recently gone for the ph1 airbox setup, but the airbox only had two clips and i thought this was ok. anyway i took it off and the box wasnt that tight so i 'adapted' some tie wraps to close the box up as it shoud be. i did this in the morning and the journey from work to home it has gone from 29 to 30. ok i no its only 1 mpg but its a start ha ha.
As for gains i can tell it pulls better mid range and throttle response is much better. i wasnt expecting any thing major in regards to gains, but my future plans are matched inlets and a nice remap from paul at RS tuning.
thanks
Antony