I'd retrofit the BMW nav and be done with it tbh. Granted you don't get full postcode search, but the 4-5 digit search was good enough for me, and a recent map disc is all you need to have decent european-wide routing.
You also don't get bluetooth, a touch screen, postcode lookup, high resolution screen, modern map graphics, modern connected features, etc etc. It also won't show media information whilst the map is visible (Unless you have the map in the tiny little assist window). You don't even get a clock or time and date display with an E39 retrofit unless you also retrofit a high onboard computer instrument cluster.
It's a pros and cons thing and I'm beginning to think the pros of the modern functionality outweigh the cons of the Bezel not looking quite as good.
I want a system where the default view is a map showing exactly where I am with my current media information displayed in the corner. BMW's system cannot offer this

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