I've bought a couple of the hybrid stepper kits from them and they have worked well. they sell a double nut ball screw kit that I put on a G0704 mill and I'm pretty happy with the results. I know they sell a PM25 screw kit, but don't know about the PM30. You can get the same ball screws and nuts etc from ebay. The imported aren't too bad and a couple of the sellers have good reps and will cut the screws to length and machine/thread the ends for you for pretty reasonable when you order if you don't have a lathe or would rather not mess with it. I'd head to the cnczone and do some research and see what folks have already done with your mill and get some insight. There are likely a few different ways and types of mounting and driving things and researching them all, looking at pros and cons and deciding what best fits your needs and goals is the best approach. I decided to make my own motor & bearing mounts etc and it was a fairly straightforward process. I had already converted a little machine shop mill so knew what to expect. You may have to mill or grind out the table saddle to make room for your ballnuts but otherwise most mods are pretty much bolt on even if you build the parts yourself. Overall it's a fun project and nice when it all comes together.