The Vidar has MANY issues with going into protection when speakers run below 4 ohms. There are countless threads to back this up. The Aegir is a lower power, sort of class a but not really that can’t drive anything challenging.
Neither will power magneplanars well. This has also been well documented. If an amp manufacturer doesn’t want to tell you what topology it is - run. Run away and take your money with you.
As for preamps, the Freya has good specs but has a host of issues that spans all of its revisions. Thought it has improved many still find the chassis rings, also gets hot, loose single ended connections, supplied tubes are unusable, and the volume ticking sound, which is a “feature”. The Saga is a solid state preamp with a tube buffer. It seems to be ok for what it is and what it costs.
This post is utter nonsense and it's too bad that trollers still frequent this site. The chassis doesn't ring, the connections are fine and the tubes are wonderful. It does get hot after an hour in tube mode, but it's designed to run like this. And again, Stereophile lists the Aegir on it's Class A listing, right along side of amps costing over 100K(look up that list and prove me wrong). I wonder why they did that? Maybe because it sounds so amazing.
Also, yes the Freya+ is fully balanced, for those who have fully balanced sources like the Bifrost and on up in their dac line.