Nice! I'd love to hear it. Start posting some vids, dammit!!
Interesting solution I found for quieting it down when going past The Man.
Get a pair of quicktime solenoid actuated valves like these.
However, mount them IN LINE with the exhaust instead of as an auxuliary dump. Drill a couple holes into each plate, on the side of the butterfly that sits flush against the lip when closed, so exhaust pressure keeps it closed shut. At lower speeds and engine RPM's, you'll end up creating an extra chamber in your exhaust that'll quiet things down significantly, especially if police are about to get nearby. Even if you rev the motor, it'll still be quiet
You can always flick the switch and open the butterflies fully for your normal straight-through piping. This setup was what i'd been planning to use on my car until I ended up buying an active silencer for the sewer pipe tip.