I have one fitted and it does help the engine breath better. The actual intake pipe is larger than the bsh and it measures just under 3inches in diameter so it can shift a lot of air. I removed the heat shielding and find the engine performs better with the full cold air flow from the front. I have always fitted K&N filters to my car as I have not used a bad kit or experienced any problems on any of my cars in 14 years.