Personally I wouldn't recommend the speaker change until you upgrade the amp and and a proper two channel preamplifier.
The problem with much more reveling speakers is that they show flaws in the system.
The Anthem is a fantastic processor, but a good tube preamplifier will outperform the Anthem and it is easy to incorporate both into a system.
I don't know which Sunfire amp you have but again, with these two super speakers I think you would find a huge improvement by upgrading to a higher performance two channel amp.
So I would say that unless you are willing to take on the entire challenge you may want to rethink this upgrade.