Magneplanar 3.7 - recommended preamp and amp

I've owned the 3.6 speakers years ago and really enjoyed them. I want to buy the 3.7s and also need electronics. I have a budget constraint of 4-5k for a solid state preamp and amp. I'm okay buying 2nd hand. For those who own Magneplanars can you recommend gear within my price range? My room size is 16 x 21 and I don't listen loudly. I thought even an integrated amp might work (like the Moon i7). I'd appreciate hearing some ideas.

Thanks!