I've done all of mine, and whilst I had a couple of hic cups it's probably down to the poor internet connection I get here out in the sticks!
There is one thing though and that is for new installs. Just didn't work for me, and on taking it up with FSB support apparently there were a couple of files missing in the zip file. The workaround I use is to install on 2.5 and then upgrade, as this uses the 'missing files' from the original version.
To the more educated there is sure to be a better way, but this works for me.