I'm actually using E46 M3 rotors they fit fine, as do stock E36 rotors.
The big bonus on this particular bearing was it was free. He had a bunch of spare parts left over from a race team.
It will get me through the season one way or another.
I'll measure the flange when I get time. I'm pretty sure it's an ecstuning BBK that I was looking at that didn't fit.