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Leaving them on 24/7 may be bad... But I've run mine for many hours and they don't really heat up. I'd be more worried about accidentally punching the woofer or something since they have no grilles

It probably is overkill to suggest this because of what you just specified. In addition, the darn taxes in Europe can easily spoil the party.
 
These speakers are more expensive than what you have in mind. They will benefit from a good PC system feed, and DAC. In addition, they will fully exploit a beefy quality power amp. So, the costs add up.

That said, I have never heard anything for a desktop system like Magnepan's Minis.
 
The resulting sound is superb and their imaging belies their size and placement. Even though Magnepan dealer locations are scarce, if you have one nearby in Norway, they are worth listening to.

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There is no need for them to be on when you are away,don't you think?
Very important rule:
FIRST you turn on the source and after your speakers.
FIRST you turn off your speakers and after the source.