The black replacement coil does not allow for the brake light function. You will no longer have a brake light.
I have to wonder What is the reason for hacksawing the OEM coil?
Doesn't the brown wire from the old condenser become the new external coils feed/signal?
I see that Myron says that if the secondary winding are not deleted they could cause misfiring. Misfiring how? The winding no longer communicate to the spark plug. That is the job of the new external coils hi tension cable.