Krell KAV-300i/ Moon I-5.3 for Krell Resolution 3

I recently bought a pair of second hand Krell Resolution R3 speakers (original stands included), in rare and very nice black piano finish.

I'm considering to upgrade the amplifier which I'm using for a moment (ols Rotel RA970bx), which works suprisingly fine, but surely not up to the task of quality the R3 deserves.

Ror now two integrateds ar in option: a used Krell KAV-300i (around $1k here) and ex-demo Simaudio Moon I-5.3 (around $2k); I have experience with both amplifiers but always in different system and never heard Krell speakers before.

Any comment and first-hand experience appreciated; also, any other sugestion for amp (used or ex-demo) up to $2k are also wellcome, keeping in mind that I'm living in Europe and many USA brands are not available here.
Thanx in advance