Shapeoko spindle options
The Shapeoko 3 is provided as a kit, so you’re welcome to customize it to your liking, with the understanding that you will be “on your own” for any and all modifications you’d like to make.
That being said, there is a PWM output on the board, which you can find in the diagram in this help article that you can use if you choose to develop your own spindle setup. You will need to provide your own power supply and motor driver, and probably will need to cut a custom bracket to install your spindle in. You can find the necessary dimensions for redesigning your own bracket here:
However, before you dismiss the Dewalt Makita trim routers and go through the trouble of switching to a different one, you may want to see this video of a Shapeoko 3 cutting through aluminum quite handily with it. For ~120USD (at the time of writing this) on Amazon it’s not a bad option.
Note that due to the microphones on most phones and noise-cancelling algorithms, the running sound of the spindle is louder relative to the cutting of the material in the video than you would perceive it if you were in the room—it’s actually a pretty quiet router, the majority of the noise you’ll experience is material and operation dependent.