The sound is an expected and understandable result when taking a big V-8 engine from something like 200 hp to 400 hp.
But when a HD gains 10 or so hp from it…
And still weighs 850lbs or more…
Then it’s just for the noise.
Yes, many will say “Loud pipes save lives” but most of that noise goes behind you.
I’ve heard people make fun of other riders for “dressing like a traffic cone” while they have the smallest taillights and turn signals possible. That’s fine, but it’s hard to take them serious as an advocate for motorcycle awareness when they also say “Loud pipes save lives”.