The strings Jim makes for the Centaurs are made from Rhino, a very good fastflight material developed for cross bows. Jim has specifically chosen it for its durability, noise level, lack of stretch, and energy transfer. SBD are made from D10 which is also great stuff, frankly not sure that there is much difference in the end materials wise, but me personally since a Centaur is such a no-compromises bow why not get one of Jim's strings that he specifically intended to work with the bow as he designed it? Just a thought. Don't get me wrong, I love Pierre's strings. But Jim isnt just slapping together a half assed string just to make the bow 'functional'...he lays them up a certain way, he uses a particular loop size to work with the bows nock grooves, etc. Might sound silly to some but my Centaur bows will wear a Centaur string. You gotta love the Navajo wool silencers too. Great stuff. And yes the Carbon/boo bows have a slightly different tone and shot feel vs the glass. The glass feel/sound softer.
I guess my bottom line is Jim puts a lot of thought and effort into every thing he makes/designs/sells. He's all about the total package.