I have the Dynomax Evolution Competition on my 3.8 JKU hardtop.
30 years ago I would have said it sounded awesome! Today, awesome but obnoxious loud to me.
But .... i'm leaving it on because the mid-range boost it's giving the Jeep is great. I drove to Moab in July and was able to maintain speed on spots where I usually had to slow down.
There is drone at 65mph that was really obnoxious with the hardtop on and turning up the radio just made more noise - very difficult to carry on a conversation.
Almost removed it before heading to Moab but I had some boom mat and laid it under the carpet covering as much of the floor front and back as possible.
Didn't have time to stick the boom mat down properly but just laying it down made a difference. When I roll the window down or sitting at a drive-thru window it's loud.
I ordered the Dynomax bullet to convert it to a quiet crawler, really hoping it tones it down.
If I leave it on I'll install the boom mat properly as well.