You are comparing two different model of cars for the same brand name. Personally, they are just the same driving feel on two different ground distance. It depends on what you need the car for?
Nowadays, SUV is very popular because they have better driving visibility and safe to drive in winter. But, it consumes more gasline than 325CI. If I were you, I would buy a X3. It's like a Baby X5 but not much different in terms of basic features. For the 325CI, I know the feeling of getting a two door car. They are stylish, attractive but not very useful. Also, their resale values aren't as good as sedans or SUV. It's really up to you. Good Luck