Jon - Thanks for the Bryston idea. Indeed Classe DR9 is polite and a little "tubey". Bryston might be a good counterbalance.
Pops - I have never felt the need to better my CS2 2s. I'm looking forward to hearing what my XO upgrade work might bring to the table. Mine are pre-production, custom voiced prototypes, but at 28 years old are nearing their electrolytic cap lifespan. With SpectraFoo, and possibly Klippel, I will be able to re-balance all circuits for the very played-in drivers.