I went through the Magnapan stage about 10 years ago, loved them and miss them. I had MMG’s, MG3A’s and 3.6’s with Mye stands. I used a BK 7220 with the BK preamp that had a passive mode. It worked well. You can find those amps for about 500 or less. Then I went with Khartago mono’s, a step up, then moved on to PASS X250 (The beast) with quality.
I saw here on A-gon the Nakamichi PA7, which is a PASS/Threshold amp for about $775, that’s a great amp and when you have time you can send it to someone to freshen up.
Then I would recommend moving up the Magnepan line .7 or the 1.7’s. Don’t buy old speakers unless your willing to re-glue them or send them back to the factory. get serial numbers and call the factory for age. If its less than 5 years your Ok.
Just my thoughts....enjoy