A:AnswerThe length of this card with the Z support bar installed is roughly ~377mm in length. I'd just round up to 380mm just to give yourself a bit of extra room to work with.
A:AnswerSame GPU but different clocks. Interestingly enough, the cheaper of the 2 SKUs at the moment of writing is the black edition with slightly higher clocks so there's a win there. Also, something to note is that the black edition has a silver backplate which is a little funny =)