CJ Premier 12's and Silverline Sonata's??

I am currently runnning CJ Premier 12 monos with Thiel 2.3's and have been considering replacing them with Silverline Sonata II's.I like the Silverline's cause they are a very efficient speaker and because I am running tube amps.I also know that my Thiels are a much harder load to drive.Although they sound fine,I believe that they would benefit from more power.I do not want to part with my amps because I really like what they do to the music.My question is....does anybody have this combo and how does it sound and is my thinking right on the efficiency thing.Thanks
Dave