If its possible keep it as it is. But there could be some drawbacks, like no postprocessor for the CAM you use, limited to 2.5D, limited file size and so on, where making it to full 3D, 4 axis and more, could be extremly expensive.

With software like NX you could write your own post processor, but if its 3d capability is not unlocked, forget about it and convert to Mach3, especially if you have to feed the file in chunks.

Obviously depending on the type of Servo controllers/ what signal they accept/ you could use the 6 Axis professional CSMIO motion controls. Which will set you back ~700 euro. Thats all.