The minimum requirements for RMA are the same as for T-Stats. If your current T-Stats server (and workstations using T-Stats) meet the minimum specs for T-Stats for an organization of your size, they should be adequate for RMA. RMA adds additional components to the existing T-Stats data warehouse to support the RMA. The RMA data loads as part of the nightly T-Stats load job, and thus adds some time to the duration of that run. However, that time is usually comparatively small to the overall duration of the T-Stats load, but of course varies based on the actual data and server involved.
The Software and Hardware Requirements are included in the T-Stats Installation Guide in Chapter 2.1: Software and Hardware Requirements.
RMA is currently compatible with both T-Stats v4.5 and Tessitura v12.5.1.