:-D ... this template includes _all_ Vienna Instruments for MIRx preset creation. It was never meant to be used with all instruments playing at the same time. But as long as Vienna Instruments are set to open without any samples loaded, this setup won't make any recent machine sweat (... provided there's enough RAM for all the pre-rendered IRs, of course).
By today's measures, my MIR development DAW is a below-average i7 based machine from late 2012 with 32 GB RAM. I did stress-tests with about 190 instruments playing inside MIR Pro in stereo setups without drop-outs, and about 90 in a 5.1 setup (using Windows 7 64-bit as OS). Latency was set to very high values for both the RME audio system as well as MIR itself. Modern machine will outplay these results easily, I assume.
/Dietz - Vienna Symphonic Library