OP, here's my question.
Are you going to run the SSR with the BBK? If so, I highly doubt that it'd fit, diameterwise.
Reason being is because the SSR has step lips, thus the inner diameter is going to be smaller than regular 19". These BBK requires 19" wheels to clear, so I'm afraid that you may run into the problem.
I too have the Rotora 15" BBK and when I chose the wheels even with 20" step lip, it won't clear the diameter.
I really hope that you prove me wrong, that way I can get a set of 20" step lip wheels for the G35