Went to BMW Artarmon last Saturday and was able to test drive both 323 and 325. Although you can feel that the 325 is the more powerful performer, the 323 has more than enough grunt for driving around the city. It feels plenty fast enough when accelerating. Comparing the two, I think that the higher premium of the 325 does not justify the power difference. As one poster said, it's either you go 323 or jump to 335 -- he is right.
I am now decidedly going for an E92 323. My next phase is to shop around for the best price.