hi guys i am removing my acoustic valve when i know how to do it 100% lol but when this is gone i want a nice cold air feed from the front to replace the valve taken out!!! what length do i need ideally and what size in mm i looked down there the other day and it is so bloody tight in the full phat 172's its unreal!!! and better still where can i get one from and what price delivered need one asap cheers many thanks for all your help