Hi Geoff,
there are several of us here who have TCLs of various sorts. Mine is the 125, a very early model. I've replaced all the electronics, apart from the power supply, contactor, & spindle drive. I use the Arc-Euro stepper drives & a breakout board of my own design. I'm just about to replace the z stepper motor, as I keep getting what I think are resonance problems on rapids & losing steps. As for software I am, of course, using Mach.
Tony