I started with the thrush welded and for me, it was too loud. It rumbles and sounds good, but it's just too noisy to me. Moved to the thrush hush after that and I love it, fun but quiet idle-1k rpm, then gets quiet and all you hear is the tractor engine whirring between 1.5-3k rpm, then it gets a little rowdy when you come up past 3k rpm, which is right around when i shift.
so the hush thrush would be my recommendation.
although i did have a dynoflow* turbo muffler before the thrush era and i loved the way it sounded. would've kept it if i could. so the thrush turbo might be nice too?
You can't go wrong with the turbo or the hush. Keep in mind they are both less than 17" overall so you might have to add a little to your tailpipe.