I purchased a 3040 CNC router off eBay a year ago and would like to change the controls. The steppers are 185oz.in motors. My question do i need to purchase a interface board and break out boards?

When dealing with 3rd party machines, we have a universal setup that will fit almost any other machine, although please take in consideration the specifications in which your stepper motors and drivers are used and set to! Now changing the controls, would be more or less changing the Breakout board/interface board to a different one that might use a different program to run your machine. Usually you will not need to change your interface board or breakout board, unless the 3rd party manufacture made it specifically to that set up.