How does separating the CC and CQ CM Server to the new CCRC WAN architecture impact performance?

I am planning to migration from CC/CQ/RP to RTC later this year. The ClearCase migration could take a year or so. Would you recommend upgrading from 7.0.1/7.1.2 to 8.x knowing we are moving later? I am NOT planning on the schema upgrade. Also, would you recommend rolling out CTE if going to RTC?