I've only owned this car for about 7 months, but I can assure you it's been a privilege. The inline 6 provides plenty of power with surprisingly-quick acceleration, yet very efficient. It seems to have a perfect balance of highway comfort and performance that begs to be driven through the bends faster than you thought possible. The driver can get all the info he needs from steering response and the pedals and the 6-speed Steptronic is a blast. There really are two ways to drive this car: like a true luxury sedan or a true performance sedan. Either way, it's darn near perfect.
6-speed automatic with Steptronic: the best automatic I've driven. The power feels sensational coming from a car like this, and it's always smooth and sensual. You will never want to get out. Stereo sounds awesome and it's plenty comfortable. Lack of a spare tire means more cargo space!
If you want even more performance, go for a 335i. iDive isn't a bad option to have (mine doesn't have it). Sport package is great too, but the standard model I have doesn't really need a firmer suspension. It handles just fine. Improve the stereo controls.