Hi, your amp will be happy with some more sensitive speakers. And just remark, your room will allove you to select also some smaller floorstander. You have nice budget. Something like Fyne Audio F501E floorstanders will be starting point or some used Proac Tablette 10 if you wish high quality bookshelf speakers. Or Q Acoustics 5000 range or Concept range will also fit well to your Marantz amp. BR