If I missed anything, let me know and I will answer any additional questions.

Power: Absolutely amazing. Lots of low end torque and at higher speeds it just flies. The steptronic shifts so swiftly, you even forget that it has to. I had a '99 328 for a couple of days before getting my 325xi and I can tell you that the power is very similar. There is a noticeable power increase going from the 323 to the 325, no question. The changes are positive. The exhaust note of the engine is a growl, and the crome exhaust tips make it look like a beast.

Xi - AWD: A lot of people here say that the extra weight (90kg) makes some big difference. Well it doesn't.
It makes the car corner like it's on rails. I almost got an A4 before I got this car, and now I am really happy I didn't.
The Xi sports wheels are beautiful. Before I got this car I saw them on photos and I didn't like them. But in real life they really make the car look classy.

Steering!: It is softer then the 328's at lower speeds and when parking, but at full throttle it is SOLID.
S-O-L-I-D, in case I ever have to repeat this one again :)
Driving 90mph - it is as stiff as the 328.
(BTW, I haven't driven a 330)

Interior - Doesn't have the silver trim (really cool looking) around the gauges as the 330. Everything else is the same as the 323 - in other words - sweet.
The steering wheel is a little smaller than last year. However, I like it, and the way it looks. The buttons are little but look better than before.

NAVIGATION The screen size hasn't changed to 6.5" as the website says. It is still the same as last year. But it's definitely worth it, as it makes driving around the hectic city of Boston much easier. The precision of the voice instructions is surprisingly good. It is also cool to have an interactive map when driving.

Here is a pic of the car: