I have the card to the built-in N swapped 2230, in order to take advantage of the 5GH band can. WiFi with 2,4GH or 5GH goes quickly and smoothly. WiDi works also, as far as I could test it.
And I almost forgot it: Bluetooth also makes what it should.
Addendum:
After further testing, I can state that Bluetooth is running even better than that of the previously installed N 2230 (faster, the mouse tuts liquid). WiFi is perfect.
According to other recessions and my findings is likely the Centrino Advanced-N 6235 harmonize well with Dell notebooks.