I know this is a v8 discussion, but I will note that I upgraded from a v4 with an ID40 to v6 with an ID41 and the sound difference with the ID41 is considerably improved. So going all the way, but only make it better.

Thanks

Primary: MD600, MS200 (SpeakerLink to AES), Trinnov ST-2, Ayre V6-xe, Salk SS8 3x LRC.
Secondary: MC600 (whole house).
Zone one: 568.2, G57, MS200, Spatial Hologram M2SE.
Zone 2-6 (Awaiting assignment).