Just like the original SE II performance mufflers of the late 90s were made by Supertrapp and I think Kerker was producing some too.

 

They still have a Supertrapp based system - SE Fatshotz that (oddly) come with an open end cap. ST and Kerker have been in bed together for a while now.

 

the fatshotz are for catalyst headpipe hence the open end cap.

 

I'm not sure this statement is accurate, If I remember correctly the Fatshots came out in 2007. Harley did not start putting catalyst in the head pipes till 2010.

Again if I remember correctly I believe the super trap version with the domed end caps had a sound level of around 92 decibels which is the same as the stock Harley Mufflers. Super Trap Fat Shots with the coned open end were considered there race versions and were 6 to 8 decibels louder.

All of this was of course depending on the disc stacks and can be adjusted as needed.

I just Purchased a new 2016 Road Glide Ultra and this is one of the exhaust I am considering for it.