I was having problems with my D2G lately so I've been calling tech reps for the last few days. I asked him if GB was coming for our phone (again) and his answer supprised me. He said that running GB on a D2G wouldn't be all that good and asked me if I knew about "rooting"? I was kind of caught off guard and said that I've read about it but thought it voids the warr. He said that no it doesn't because your only improving not totaly changing the phone (thats when he mentioned SPF'ing back to stock). He said that the only thing they frown on is "overclocking" because it burns up the phone quicker. He even suggested getting Titanium Backup to freeze the blotware. Strangest call I've ever had with a Verizon tech rep.
So, Root and Rom to your hearts content (just don't overclock)?