Depending on your budget I agee Coda makes very good underappreciated amps. They fly below the radar. Your room isn't that big too but high amperage they put out is rather robust. That helps with the lower listening levels. A #16 would be magnificent. (I too have the s5.5 and it is amazing) Good luck making those Magico's sing.
Best amplification for Magico S3 newer version on your experience
I purchased a pair of S3 but now I am facing that I might not have the funds for top brands amplification that I see them pairing at shows CH, Solution, D'agostino
Etc.
I come over here looking for advice.
Currently using Luxman 509x. My room is 18x12 and I listen to low to moderate vol.
Thank you in advance.