I prefer the tapered cone because it allows for more airflow to the lower portion of the filter.
The wheel well cuts in at a angle and really restricts the filters ability to get airflow if you jam the filter right up against it like a straight round filter would be.
Also it you do not do that you would lose out on filter diameter and/or filter length which exponentially decrease your effective filter area.
So to make my posts short I just say I recommend, "a Large mouth K&N Conical & MAF adapter"
