Yes.. here is a pic of the MAF stock airbox and intake tube

 

I've recently got a Baily DV 12 dump valve for my 03 Impreza, It's running 330BHP and I'm hoping for better response thru the gears. It appears I made the right choice over the blow off valve?

 

holy 6 year old thread...

 

They are the same thing, however bypass valve is just a BOV with a recirculation. See, the turbo sucks so much air in from the MAF, and when you release this pressure into the atmosphere, the engine doedn't end up seeing the same amount of air that your MAF saw. What this means is that when you shift you will be releasing metered air into the atmosphere, and for that time your car will run very rich.