which u guys perfer.
Reference 54
Reference 36
or their predecessor
Mark IV

This is for the tnor sax btw. i know the MKIV`s r most known for their altos iof that helps.

MKVI, hands down. Their new references are nothing to the old ones. I have found that (remember, this is an opinion) Selmers new references are a sure sign that they are becoming desperate. Their recent attempt is to reference the new horns to their best creations, bringing many players off their own vintage selmers to try new ones. There are better horns out there, and to me, the MKVI series is.