Wow, you were both fast on the response; thank you. I'm still getting up to speed on the terminology, so hopefully, I didn't misspeak. The second board in the case is a JP-1635A (see attached), so perhaps that's the motion controller and the JP-3163B is the stepper drive?
Through projects at work, I've had experience with Pokeys boards, and it appears to be a cheap solution with good customer support. I hadn't seen the PDMX-424, but it also looks like a good solution. Considering Mach4 is the future, I felt it was pertinent to go with this version over Mach3. Am I hearing that it would be best for me to replace both the motion control and stepper drive boards for better options that are guaranteed to work with Mach4?