I'd recommend leaving it alone as the standard airbox is pretty well designed, is not particularly restrictive* and is already placed to pick up cold air. Don't touch junk like this overpriced tat with a barge pole as regardless of advertising claims they won't do anything except look chavvy and make it louder** while increasing inlet air temp because they're an open cone filter sitting right near the exhaust manifold
* AIUI the e36 version of the m104 used basically the same airbox with an extra inlet hole knocked in it however the inlet pipework that passes over the cam cover is larger i.e. the standard filter element itself is more than enough for the 3.2 m104.