Reporting back.... the mk3 bass is much better and more defined, and the soundstage has opened up. The differences between the mk2 and mk3 are subtle, but IMO worth the money. I now have the mk2 for sale.
I will also try out the new WAVE and SINE devices. I used to have the Qv2 and while it did improve things in some areas, I thought it ultimately took away some transparency and naturalness. I ended up liking my system better without it in. But that was a while ago and many things have since changed...