Sound level of the new exhaust seems roughly the same as the old one. The normal mechanical "dieseling" noise from the engine (which hasn't changed) sounds louder than the exhaust. I never really thought about that until trying to listen to the new exhaust. The LB1914's engine bay is just metal panels with no sound deadening/absorbing material on the inside (and plenty of openings for sound to escape).
I'd call the replacement a success - I spent a little bit of time and effort to save some money compared to buying a new OEM muffler and now the tractor is functional again. Going to pull the new setup off at some point and paint it black with high-temp paint.