550i vs M3 (Which way would you go?)

I've been going back and forth through what feels like the entire lineup (no x's) for months now. At this moment I'm trying to decide between a 550i and a M3 (new lease). I'm in a '13 535i right now. I'm sure there are some simple luxuries that I might miss, but the ///M3 is obviously attractive for so many of it's own reasons. Prices are super similar with the way I've been building them. Just trying to get some other opinions to see if they stir up some swayings in my own mind. Thanks.

Pics of what I'm thinking


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550i vs M3 (Which way would you go?)