Sophotrope

Has anyone tried making a custom exhaust with Varex mufflers?

Or for the DIY crowd: has anyone considered making a variable UK mod with an electronically controlled exhaust bypass valve?

I'm looking to make an exhaust system which is stock quiet (read chambered exhaust --even a "quiet" straight-through exhaust like Mugen is loud as f*ck compared to a chambered exhaust) when I want, but at the flip of a switch can become a loud, unrestricted beast. I'm concerned with maintaining stock noise levels when I am driving around town --at the expense of perf.-- with the ability to allow significant flow when wanted --so as to not restrict the high end of my FI setup.

Has anyone done anything like this?