I took the car into Nissan today and I asked about various mods and they said that pretty much anything is ok and wont void the warranty as long as the mod was not the direct cause of the broken part. I.e if you make exhaust mods you are fine, if you do a Cobb tune or something like that you are fine unless it was the direct reason that the engine blew up or something like that. They even said that dispite what has been said they can track when the Cobb has been switched on or off or the tune was done and they are ok with it so there is no need to hide it.
As far as the VDC goes you can drive with it off but they will be asking questions of you if have a warranty issue while it was turned off. If you are trying to free yourself form snow, sand etc that is fine. Just dont think you can fly around the street wuth it off and blow something up and expect it to be covered by warranty, it all sound reasonable to me.
The other pretty much amazing thing they said was that they are more than happy to work on any JDM R35 as they have invested all the money in facilities and staff training so they are more than happy to work on ANY R35. That comment was contrary to pretty much everything that I have read and heard.