In Reply to: Ali B. forgot to mention... posted by Gilbert on April 14, 1999 at 19:17:36:
$600 gives you 15" alloys on 195/65R15 tires, whereas the 328i comes with 16" alloys on 205/55R16 tires. 16" alloys are not available as standalone option on the 323i. Also, without the Premium Package, the 323i would not have the dual power seats with driver's side memory that comes standard on the 328i.
I am sure you can configure a 323i in a way that the difference in price relative to a 328i is more than $4000, but the equipment levels would not exactly match. I was trying to compare two cars that were as close to each other as possible in terms of equipment level. I agree with your assertion that the gap is too much for the incremental power gain.