I was a Magnepan dealer for many years and have personally owned almost every model they've made. I have also tried many, many amps with them.
For your budget, (used) I would recommend:
Odyssey Stratos Plus or Extreme. You might be able to find a pair of the monos for maybe a little more.
Belles 150A Reference
Emotiva XPA-2 or if you can find a pair, the Emotiva XPA-1L (Class A) mono amps are incredible.
There are a lot of others too. I'm sure you will get many recommendations.
For your budget, (used) I would recommend:
Odyssey Stratos Plus or Extreme. You might be able to find a pair of the monos for maybe a little more.
Belles 150A Reference
Emotiva XPA-2 or if you can find a pair, the Emotiva XPA-1L (Class A) mono amps are incredible.
There are a lot of others too. I'm sure you will get many recommendations.