LOL - I've been reading this thread and have the feeling that some are missing the point.
I don't think the OP was asking if the M50i is performing, handling or what not like the X5 M. I also saw posts here with diagrams of specific parts that are on the X5 M.
Again, I don't think that's the point.
IMO, in the end, you can call it marketing BUT the final decision what is officially an M or not is made by BMW and that's what they did: They officially consider the M50i an M.
For me, on my former X7 M50i, it did not really matter. I could have gotten a fully loaded X5 M competition for the same amount of money but I did not want to sacrifice on comfort.
If you are going back to the roots of BMW M, I bet many would have a hard time considering
ANY SUV to be a true M.
When I was young, a BMW M was, well, an M3 and nothing else...
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Gone: 2020 X7 M50i, Mineral White, Ivory White Full Merino, Piano Black Trim, Cold Weather, Dynamic Handling, Driving Assistance, Luxury Seating, Executive, 22" Y-Spoke Orbit Grey Wheels Style 758i, Space Saver Spare, Trailer Hitch, Leather Dash, Ambient Air, Bowers & Wilkins, Rear Entertainment, Night Vision, Extended Shadowline, Alcantara Headliner in Upholstery Color.