Separating the CC and CQ CM Server to the new CCRC WAN architecture impact performance?

We have not seen any negative impact on performance due to the separation of CC and CQ servers.

Single user performance is not affected. Where you will see a difference is on servers where CC and CQ CM Server may have been deployed on the same machine. In 7.1.x, CC and CQ CM Servers shared a profile by default. In v 8 they are in separate profiles  by default, hence separate processes. The servers are not contending for the resources of one process thus improving scalability.