I recently sent in my MBP for some unrelated repairs and it was returned to me with an OEM Wireless G card. I had previously upgraded it to a wireless N card myself. I seem to remember calling Apple at the time and asking them if the upgrade would effect my warranty and they said no, just that the new part would not be covered. Now that they have stolen it from me, I wanted to double check the policy before I talk to them again. What is the policy on doing your own upgrades?