Servo motor to drive spindle, good idea or not

Hi, I purchased a second hand milling machine which came with CS-LABS CSMIO/IP-S controller and the CSMIO-IO module expansion unit and hand remote. I have not powered up anything yet as the machine was in parts when I purchased it and I need to put it all together again. Now I know that CS-LABS control units are build around Mach3 or 4. The stepper motors are open loop 12nm units.
Now, I have a licensed copy of mach3, I am not really interested in buying mach4. However I also have a centroid acorn board and the milling software and some 12nm closed loop stepper drivers and motors.
My question is would I be better off using the centroid system with the closed loop motors, and buying a servo motor to run the spindle. Or buying mach4.
If I was to go the servo motor to drive the spindle would a 1KW motor with belt drive do the job, if so which one do I buy in the U.K. and from where. Would a servo spindle motor allow me to tap holes. And do I need a motor with a brake.
I don’t want to spend a fortune, it’s only a hobby, but I don’t want cheap breaks in a year or less rubbish. The mill is the optimum bf30 machine.
Thanks