I posted a while back making some small parts in 17-4ph stainless on a $500 desktop CNC.

The removal rate was slow but acceptable. However, I had some mic6 offcuts laying around for another project, so I used the machine to upgrade itself.

20mm mic6 side plates, nearly doubled working z height.

1.5kw vfd spindle replaced the old 300w dc motor.

In aluminum, my material removal rate is now 25 times what it was stock, and no more chatter. Should speed up my projects quite a bit, and any other upgrades seem moot at this point. Absolutely incredible to hear this thing sing with just a new spindle and some scrap aluminum.