@palmcoastg35,
Good News, all of our Deco Products are meant to work together, allowing for additions such as this.
The features of your network are primarily decided by the model of the main router, allowing access to the newest features by switching just the main node.
The network that is provided by the satellite unit is subject to the normal constraints of the Wi-Fi technology of the node, its backhaul method, and the interference from other wireless devices. Essentially it will provide a wireless network as it is capable.
Your network will generally not see a decrease in performance, as the network will optimize itself to provide the best connection across all the nodes.