I would just say that while the money is still in your pocket, you should listen to a tube amp that is capable of driving these speakers like the Wolcott. I have not heard the Rowland Model 2. I have heard the SA-100 and I have heard the Extremas, although not together. My guess is the SA-100 is going to be exposed by the Extremas, because the Extremas are very revealing through the mids. The Plinius gear is great value here in New Zealand, but I cannot see it as great value in the US. I believe it has become somewhat over-rated (but then again so have others). The problem I hear with the Plinius is a touch of artificial warmth in the upper bass and lower mid-range, which then transitions sharply to an electronic hardness (significant)and brightness (slight) in the upper mids and lower treble. The mid and upper treble are reasonably seemless with decent resolution and air, but are a bit cool. mid bass and deep bass are the areas where the Plinius is much harder to fault. It is a very good bass amp. By reputation, I would expect the Rowland to be smoother than the Plinius and therefore possibly better with the Extrema, but don't take my word for it. Hopefully someone can help you on the Rowland.
Plinius SA-100 vs. Rowland Model 2
anyone able to describe the differences between these amps from personal experience - they will be used to power Sonus Faber Extremas - I am looking for more transparency and dont listen at high volumes (the Extremas seem to be susceptible to treble glare), and clean (not fat) bass