Tellefsen, its a nice dilemma to have. I have heard your speakers in the distant past, and from sonic memory, they were fairly neutral. If your sonic bias is already titled towards tubes, a switch to SS may not be wise. Another phile who owns my speakers (Fried Reference) also owns the Viva monos along with a Viva pre-amp and loves them to death. I myself have fiddled with SET amplification (Kora Galaxy, 50W) with the Dude. As expected, it did some things better than the Samsons (in my system), including texture, and sound staging, but the Samsons are so dynamic and bristle with lifelike energy that they made the Kora sound pretty and polite...almost dead.
I think the obvious solution (stated above by Jtwrace) is to get Paul's new GT160s. You will bet the best of both worlds....