[4RSS FED]

Thanks for the great write up. I usually don't have too much to contribute but here are some notes that may help someone who goes this route.

I have had my exhaust installed for a week but I just finished running the vacuum lines today. It took a little longer than I had hoped but the end result was worth it. I wound up mounting my switch under the dash. It took some modification to get it to work where I mounted it, but it is accessible while driving. Closed it runs nice and quiet, until you step on it. The valves will be fully closed at about 10" of vacuum (at idle you will be in the 17 in Hg range). Anything less than that they start to modulate open until you reach 0 in Hg (fully open).

That vacuum switch design, ports vacuum to the atmosphere when it is in the open (extended) position. So if you hook up your lines the wrong way you may hear the hissing noise that was described in an earlier post. See the last photo where you can see the white table through the top vacuum port labeled exhaust. The bottom port is covered whether open or closed.