the only i now is that the new 3000 series intel supports cisco extension 4.
Edited----
I forgot to mention the fact that by using any other brand than intel for the wireless module would remove the centrino brand and all of it´s benefits an discounts for the retailer.
Centrino consist of processor, chipset and wlan, if any of this is missing it won´t be labeled as centrino and this lack of endorsement will pull up the price.

check the 2 different logos (core duo inside -without intel wireless- or centrino duo inside - with the 3 components- )