I too had a pair of ARC Classic 150s for a short period. I have since learned that the 150w of the CL150s is not at all the same as the 150w on my CAT JL-3 Signature amps. Whereas the CL150s peaked out easily with the Magnepan 3.5s, the JL-3s drove these speakers with ease. And after seeing the transformers in the ARC amps vs. those in the CAT amps, I can see why! I would be surprised if the output transformers in the VTM200 are much different than those in the VT200 or VT100 for that matter.
So don't be too concerned with a power rating, especially with high efficiency speakers like the ones you own. I suspect from reading Cornfedboy's comments on the Nagra, with their current capability, these would be worth your investigation since you already own the PL-L.