I've always liked the 214's - I had them on my E70 X5, so I've been looking out for a set and these appeared yesterday with matching Michelin tyres all round for a good price.
I'd done a fair bit of research so was fairly confident they would fit.
I had 18" style 368's on when I bought the car which I've never been a fan of...
Anyway, they fitted on fine - this is just after dropping the jack so the suspension hasn't settled yet:
Here you can see how close the fronts are to the strut, which BMW have flattened a little just to make things easier!
Here's the difference between the sizes... interestingly my speedo is now reading a GPS-correct speed at 70mph, and acceleration feels no different.
And here they are on this morning:
F: 20x10 ET40 275/45/20 (X5 size)
R: 20x11 ET37 315/35/20 (X5 size)