First I know very little about CNC. I will most likely be buying one of those cheap Chinese routers (CNC 3020). I will mostly be using it for etching PCBs and perhaps routing plastic project boxes.

I thought I saw a hood on CNC machines that attaches to the bottom of the spindle and vacuums the debris from the router. Can such a hood be fitted to most routers?

Would I benefit from eventually upgrading the spindle or shouldn't I bother? It would be nice to be able to cut at least light aluminum.