After finding an ARC Reference 5SE for sale on Audiogon and losing it because I hemmed and hawed about the purchase, a second 5SE showed up and I bought it. It should arrive sometime next week. I will see if all of the praise for the REF 5SE is worth it.
I am looking forward to much better sound. Of course, having an ARC Ref 5SE and a REF 150 might reveal other limitations in my setup.