Americanflag,
I honestly don't know. Purchased the original SCIV when they first came out @ $3999. Replaced these later with SCIVA @ $8000 if memory serves.
Frankly I didn't know there was a third version. I'm not saying there was no third version, I just never heard of it. I do not, in any way, consider myself an expert on these speakers.
I do know that I much preferred the IVA over the IV for reasons expressed above. IMO: When Dunlavy tweeked the original design he made major improvements.