Just about got my air exchange system finished. So far it works pretty good. All the air from the router is blown out the side. This makes dust pick up very efficient. It allows me to use smaller hoses and smaller vacuums. I no longer use magnets on the shrouds so they are much simpler to make.
The air exchanger also allows you to attach a wrench to the main shank by just slipping it in the slot. This allows you to change the bits one handed.
I have built the system to work with most K2CNC mounts.
See it here: