You might consider changing the amp out to something like a Krell FPB 400cx, 450mcx, 700cx, or 750mcx to get the most out of those speakers; simply: they need current. These amps will get more out of your speakers than the Lamm.
Levinson, McCormick, Pass and Rowland also are candidate designs; just be sure the amp doubles power into halved loads at least down to 2 Ohms.
Also, I guarantee that if you move away from Thiel, you will eventually miss them and move back. Mark my words, I speak from experience. Once their time and phase coherence gets into you, no other design will suffice.
