Honestly, the HiFi Professional beats the B/O by miles in a cost vs. benefit comparison. The former is already very good and less than a third the price of the latter.
I would also add that my impression is that the HiFi Professional system received some recent improvements. When I tested a car January this year (a mid-2011 built 535d Touring, I believe) I could definitely feel that the sound was spatially centered too low, to a point where I doubted if I should go for it or not. In my car (MY 2013) this is not an issue at all.
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