If you are seriously considering musical fidelity, check out upscaleaudio.com. He has the m2si integrated at 40% off the 1k msrp. Unless you go used and get more for your $$$. And can stretch it a bit, this Hegel here on AUDIOGON would have plenty of power for your ls50s
https://www.audiogon.com/listings/lis98g51-hegel-h-160-h160-h-160-integrated-amplifier-solid-state
https://www.audiogon.com/listings/lis98g51-hegel-h-160-h160-h-160-integrated-amplifier-solid-state