Generally speaking, the requirements for the CE platform are driven by the features you want to deploy, the performance and the scalability you want to achieve as it is the case for routers connecting to a FR network. In many cases, it might just happen that the routers you are currently employing to connect to the FR network could also be used as CE routers.
Hope this helps,
Regards,
Harold Ritter, CCIE #4168 (EI, SP)