I would expect good things out of those turn-downs.
I'm attaching a picture of the ones on my boat so you can see where I'm coming from.
With my boat, I found that it was quite a bit quieter than my previous boat... plus I have never once been hit in the face by a bunch of exhaust. I can't smell it, and I haven't gotten a headache yet. I'm sure it's still there, but because it is so limited it is something I rarely think about. Seeing that mine are not as extended as those MBs, I'd assume they'd perform even better.
While it is no FAE, it's a pretty good little addition that surprised me.