To sidetrack a bit - one could also get a nicely equipped new 2019 Porsche Macan S for that price - which I am told drives like a car. And no agonizing about the front grille
Getting back to the point - I guess the M340 will be much better than the M550 when it comes to fuel consumption. And I think it can possibly be well equipped at 65K by leaving out a couple of options. But your point about leasing definitely stands - they might not be far apart in monthly cost.