G'Day, I had similar questions when I bought mine. Same year and model.
I live in Canada so kilometers and so on are the norm here but usually our dashes have mph and km/h. I really like it with km/h only because it provides a certain European authenticity.
In any case, the car is virtually identical to the 325i.
Chassis components will be the same, however most engine stuff probably isn't. I would suggest going to your local BMW dealer for some maintenance items such as filters and see what they say. I bought an air filter for a 325i at Napa, intending to use it in my car but it didn't fit. Strangely, the correct filter at the dealer was actually cheaper. If the dealer isn't helpful, then I hope there are others in your situation that can suggest a good supplier. The 320i isn't exactly the most popular model here in Canada, and was never imported by BMW Stateside.