Questions for Huzo. Just got my Arrow head pipes and want to do the lower muffler like you did. Can you tell me which model Mivv you have? Is it straight through with or without the DB killer? How long is it? My concern is that it may be too loud for me. I know that is very subjective. The one video I saw only shows the bike at idle. With a helmet and riding at a constant speed do you hear it? Thank you and I am happy to start another thread if you think that may be better. No hurry as I need to get the muffler and find a shop to make the connector. Cheers. 
I’ll have to go back and try to find the model number for you, it’s important to get the left hand one.
Also if I did it again I’d be tempted to go for the oval section one, it would be easier to get it tucked away underneath and still in line with the centreline. But I’m satisfied with it.
Old mate reckons when I pass him at 100 kph, it’s only barely audible, which I tend to reckon would be right.
In answer to your other questions…
I run the dB killer, it is too loud without IMO.
This is without
https://youtu.be/W9ulUhJgVwkThis is with
https://youtu.be/Li8qvFVuAJ8I’ll admit they sound scarily similar, but the second one is in confined space.
Suffice to say, it is too loud without, both at idle and in use. I find that with the restrictor in, it is ok but I would not want it louder. I’m away at present, but I’ll shoot another video when I get back with the “quieter” version out in the open.
In reality, it’s about the same as a Ducati monster but a bit more mellow. On the road at 100 kph, it’s really ideal.
I’ll get back to you.