No, but that seems to be no problem (so actually yes
, I've given that some consideration). These calipers also seem to swap 1:1 on 1 series as part of the performance package without bias adjustment.
ECS recommends when only fitting the front bbk set to use a more aggressive pad on the rear, but that's no issue now
I also didn't experience any premature lockup at the rear with brake tests and braking in the pads.
What might be an option for the future is a bigger master cilinder. Brake pedal travel incresed with this setup about 1cm or so, but the stock cilinder can push around enough fluid (there's easily enough travel to lock up the brakes)
I don't know if an z4m master cilinder would fit and if it is bigger.