Stiffing mods, either the 30 min bolts or the metal bar (you can use a doweling jig to line up the holes nicely)
Extra stiffening brackets on the Y axis.
Some people have replaced there eccentric nuts with eccentric spacers (the older style but uses more parts)
I was looking at going with a single long bolt for a wheel pair on the gantry, but that will require switching to eccentric spacers for the bottom wheels. And I am not sure if it is needed with the stiffing mod in place.
For production work always having to change out brushes on the router will be pain.
So you may want to switch to a spindle or get a second router so you can quick swap them.
I have been looking at spindles and it seems the water cooled spindles are close in power to the router. Close enough anyway, when I was loading my router down enough to be using most of its power it was way to much for the XC to handle.
I have been using GWizard to calculate my feeds and speeds. It took me a few weeks to figure it out.
The biggest tip is manual set your RPM to a lower speed to get a feed that will work well with the XC
Here was my first attempt at cutting out plywood for reference:
Cutting plywood with a downcut bit)