I'm in the same situation... deciding between 323i and 325i ... as well as the comfy Lexus IS250 as well!!
Would like to know whether there is a significant, noticeable difference in the performance between the 323 and the 325i. 325 with options is really stretching my budget. Then again there's always the IS250 with every option available and also much cheaper.
As with the chip... is that a confirmed thing or is it just something that may be possible in future?