I don't know if it matters to you but going with 2 (or more) sets of mufflers may be quite a bit easier. I built a set for my car (BDR) using V band clamps at the collector. Using these I can remove or install my side pipes literally in 3 minutes because I only have one bolt to loosen/ tighten. I think I understand your end goal of being able to switch your sound out-put quickly and I believe your current plan will work. It just seems to me that it'd be a lot easier just to swap pipes on out cars. Works well on mine and if you have the fab skills to do what you're talking about then this would be child's play. JMHO
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