Hey Richard
You can call me Dave - it is burried in my sig
. I have successfully updated two versions of firmware and I would assume so have thousands of others. As to what each version fixes you can review the
Read Me Files which have a list of fixes. Version 1.1 fixed quite a few things and only version 1.3 added SDM support. The instructions are on that page as well. Personally I think the biggest issue you can run into is if your power dies during the upgrade and that warning is there as well. If you are not comfortable doing it , download the file , print out the page and ask your camera store to do it , they may or may not. I suggest you do it , yes something can go wrong and fry your camera , out for repair, but the same can be said for every time you jump into a car something could go wrong. Anyway your call.
As for the battery grip - I am not sure. I don't think I have ever been close to having the batteries drained. I tend to recharge them after a day of shooting. That would indeed suck as you know the power would go out on that once in a lifetime shot ! Might want to start a new thread with that question.
Good Luck