I've not tried a car with Xenons. But as most of my driving is on lit roads then its not really a problem seeing the road. They might look better, but as I'm driving I'm more concerned about function then pure looks.
On the recommendation of this forum I went for the 30d rather then the 20d, and haven't regretted it for a moment. The price difference shouldn't be as great as it is, but you get the Auto and Metalic paint.
As regards delay with the Auto. Just select Sports mode, and knock the Auto lever over to DS- no delay in power!
The only problem with BMW and most car manufacturers is that you pay through the nose for extras. You can quickly make a X3 very expensive. I'd be interested to see if there's a 'Horsey' chart to show BMW profit margin per extra.
Extras I couldn't justify- Power Heated Seats (Sorely missed from last car), Sunroof, M-Sport, DAB radio etc.
Extras I did go for but expensive- Professional Sat Nav
Extras I did go for- Sports Steering wheel, and Storage Pack