Other food for thought:
Oyster looks much better than beige IMHO, particularly with dark exterior colours. You must have either brushed alu or a wood trim, the satin silver looks rubbish
I would spend the HUD money on a sunroof. Love mine.
Re. VDC, if you're worried about the ride then go for it as it should help. I would recommend a test drive though as I think Normal mode makes the car too floaty for some. I prefer to feel more "connected". That said, I have never driven an X3 with VDC. Just don't rely on reviewers calling it a "must have" option despite having never even driven an X3 without VDC. I smell a marketing trick in the uniformity of this review advice
Not sure on VSS but don't really see the point as servo works well enough for me. It would mean you'd get the Normal/Sport/Sport+ switch if you didn't order VDC
If you prefer the look of M Sport then 100% go for it instead. I personally don't because of its side profile and small-looking-wheel visual effect, and also looking too narrow from the back (less of a problem with black/CB colours) but I'm in the minority - most disagree, but hey, they didn't use the M Sport in the marketing brochures and beauty shots when it was launched, they used a Mineral Silver SE with 309s. Just get which one
you like the look of the most
For BMW Apps see this youtube clip. Don't get it for what is available now. The important part is future apps and their potential - bit of a gamble but more of a gamble not to have it IMO