PM-30 Build Suggestions

I am weighting my options on upgrading my CNC from a converted Harbor Freight Mini Mill to a PM-30. I like that you can squeeze extra y travel out of the 30 and that it has a decent sized belt driven spindle/motor out of the gate. Since I already have a small cnc mill, a cnc router, and a manual mill i was considering building my own conversion kit. I was wondering if anyone had made a G0704/pm-25 conversion work on one of these. I also am considering just buying a conversion because I am slowly and painfully milling parts that I sell online on my current machine. I am eager to get up and running and think the purpose built conversion could be done quickly and efficiently.

My second question is does anyone know how many rippems (rpm) the factory spindle bearings can handle on one of these bad boys? If I were to change the ratio of the belt drive how fast can I go? I am not looking for blistering speeds but I will be using this machine for small production runs and the more rpm I can get the better.

Any other insight on common issues one might encounter while converting one of these machines would also be awesome!
I plan to use closed loop nema 34's and linuxcnc.

The PM-30 has Tapered Roller bearing stock. They are a strong bearing but will make a lot of heat at higher speed. Most all the bench top run them.

Breaking takes a long time lets say 20 hours. If you have the preload sett correctly you can run 4000 to 5000 RPM and not over heat on long runs.

The stock RPM is 3K and getting to 4 or lets say 4500 should be fairly easy. For faster you will want to go to new AC bearings and really, if you run larger cutters at all, a larger motor. The 30 is just large enough to fit a 56C size motor.

The 30 does give over 8" of Y. It is a nice move up from the mini mills.

I also make a kit for them.
Thanks
Dave