I have thought long and hard about this myself too, I am contemplating 60 or 80 watt tube. If the laser tube is mounted to the main frame of the MPCNC even if it shakes it would shake as a unit. I have a couple simple ideas for mounting the tube. My build is 5′ x 5′ so the tube will fit along one of the Axis. Shaking should be limited as the moving mass would be much less then having the router hanging off the Z axis. Once I save the money to buy the tube, mirrors, lenses, power supply etc it will be an interesting adventure.