You may want to rethink the mill you are selecting for the work you want to do.
For several years I built and flew RC helicopters, eventually designing and building my own control schemes. So I am familiar with the carbon fiber sheeting you plan to cut and what you need is a router, not a big mill.
Even an X3 would be overkill for making RC heli parts. You might consider getting a smaller and more accurate mill and look into a high speed spindle, or plan on hanging a high speed spindle outboard on the head.
For small cutters, I have a block to mount my Dumore die grinder spindle on the mill head. I think it is in the 28,000 RPM neighborhood. My mill spindle tops out around 7,000 . . . great for cutting aluminum, but not fast enough for routing.