I owned the PeachTree GAN400 2x for my Magnepan LRS+. The GAN400 has enough power but has a bit of hardness on top.
The 2 amps that I loved with my LRS+ are the CODA #16 which is expensive and the Sanders Magtech which can be found for under $4k. The Sanders is well known to be a go to amp for Maggies.
I sold my LRS+ since I lost my room and ended up buying a used Magnepan Mini. I run it with the Sanders Magtech and it is impressive.
The Sanders is 500 watts at 8 and 900 watts at 4. It was specifically built for Maggies if the designer is to be believed. He told me on the phone.
Send me a DM if you want to discuss.