Getting one with all those options is nice, but hard to find. The 3.0L is a great engine all around! A panoramic moon roof makes the car and heated seats are dope, as long as one of them doesn't have to be replaced = they get stupid hot on level 3 setting. HID's are a must and a conversion for HID fogs is easy to do as well. Auto is fine with the tiptronic as well, especially if you roll alot on the highway. Your more than likely not gonna get 16"s dewd, i think they start at 17's? Bluetooth in car cockpit dialing is damn nice to have and if you can find it, get the garage opener version of the auto dimming rear view mirror.
A nice addition for storage is the center pocket for the main dash, to store crap like sunglasses etc... but even better is the OEM 4.3" GPS pocket and unit. Ski bag pass through is useless and make sure it comes with the trunk privacy shade as well. Seen lots of X3's (used) with them missing or broken.
We have some 20's for summer and they make the whole car for sure.
Cabin air filter, air filter, oil filter, fuel filter are common things you'll find need to be done. The "S" bend in the air intake boot often cracks and is like 80 bucks to replace. Brakes pads and rotors can be anywhere from 750-1000 for all 4 corners depending on where you get them serviced. Oil changes are to be done between 15-25k depending on your driving style, and they'll run you 100+ for oil and filter. Coolant fluid isn't to bad for 4L (about 35-40 bucks). Suspension is as spirited as you can for this class of vehicle, we chose it over an Mercedes ML350 b/c of that.
These little tanks handle like they are on rails with AWD/4x4 on with snow tires as well. We live in cottage country and put it through the worst weather in Ontario = no problems.