I am not sure about the power ratings for Vitus. However, I would not think twice about putting 600-900+ watts at 4 ohms onto the Marten.
For the Isis in a large room, with few exceptions, I would be looking at 400+ watts into 4 ohms as a minimum.
Other tricks to increase bass would be in the cables. The power cords on the source have the largest effect, followed by speaker cables and interconnects, followed by power cords on the amplifiers. Elrod power cords have a striking effect on the bass.
You have great speakers. All great systems take some time to build and refine.
For the Isis in a large room, with few exceptions, I would be looking at 400+ watts into 4 ohms as a minimum.
Other tricks to increase bass would be in the cables. The power cords on the source have the largest effect, followed by speaker cables and interconnects, followed by power cords on the amplifiers. Elrod power cords have a striking effect on the bass.
You have great speakers. All great systems take some time to build and refine.