Given that there is not alot of headroom with regards to the gain, do you think the Harbeths would be sensitive enough to accommodate this?
Well, that's the $10,000 question, isn't it?
I would think(nut not know) that the one place that not having enough voltage/headroom to drive your integrated would show up is in the bass, which requires wattage.
But, the Harbeth's are known to be easier to drive than their specs imply.
My suggestion - go for a used EXP, it is a perfect match for the Era and the front panel loading options are awesome. Give it a try, and if it doesn't work out, you can resell it here for exactly what you paid.
We are only talking about ~2dB of gain, that's real close.