I had a Stebro system on my '62 Tri-Carb back in the 1980's. It was loud, but not bothersome to me. A good friend, who would occasionally drive my BT7, complained that the sound hurt his ears, and I thought that I may be damaging my ears as well. I wound up cutting the side exhausts, and attaching stock tailpipes. Still have the Healey, but now have Falcon stainless steel system. If I remember correctly, baffles were available to insert into the side exhausts, for street use.
Jerry