Excellent write up/info. As always, the more pictures the better.
I just need the motivation for something like this. I imagine the output is excellent in the housings.
I found this on their forum, but it doesn't really answer if you can have it completely disabled. They have it listed as an option. So I would ASSUME you could have them just disable it.
http://www.greendieselengineering.com/jforum/posts/list/174.page