I had a vmc40 inspected by a tech that I am interested in, and came back with the x and z ballscrews noisey, but very low backlash, and needing a new 7500 spindle and belts. I lost interest until the seller said they would take my lowered offer. So, who rebuilds these spindles, how hard are they to replace, and can I replace it with the 10,000 rpm grease packed spindle?