i listened to bowls for a long time on my 325i's. have the 414 (aka vwap) flats with the hole cut, but the sound is just too bloated and dull, so I've kept the bowls on. but the bowls to me have a little too much treble emphasis, and the bass could use a little more body.
so about 2 weeks ago i decided to try reverse bowls (again) after about a year of having the 325i's. perfect, seriously. the difference over regular bowls is very slight, nowhere near as different as the 414 pads, which are a completely different sound (i really don't care for the 414's). but with reverse bowls, more like regular bowls but more bass presence, highs don't pierce, can turn the volume up a little more, mids are fuller. to my ears, clarity on the top end is still retained, unlike with the 414 pads, which to me sound muddy. for me, the sound is what i've been looking for. so get used to the bowl sound first, then try reversing them.