A Cambell Hausfeld 4hp 2 stage 80 gallon tank that I have slowed down about 40% to reduce the noise, as well as a homemade intake muffler. It now pumps about 10 cfm which is what my Kitamura uses as well as the Brother 27k.If you don't mind sharing. What size compressor do you have installed?
If you're doing a lot of surfacing I don't think you want a greased spindle and you will want a chiller, as well as a better control for that type of work. My 2001 Kitamura will run circles around my new Brother when running high-accuracy cutter paths, as in many times faster. My Brother sales/machine tech told me the only difference between the 16k standard and BBT spindles was the dual-face contact, including drawbar force. I do know from the outside the two spindles look identical and have the same size bearings as I watched the tech swap the standard spindle that came with the machine for the dual contact I upgraded to. Keep in mind the bore in the head is what the bearings slide into so no chance they are bigger, unless the spindle shaft is smaller. So this would indicate that ALL Speedios have the same outside diameter spindle bearings, even the high torque spindles. I sure wish these spindle details were not the national security secret that Brother makes them out to be as all we hear is bullshit gossip.If you are doing a lot of surfacing, or pretty much running aluminum (especially smaller tools) then 27K. Otherwise 16BBT.. From what I understand the bearings in the BBT are larger and able to take more of a hit without damage.