I like your style, I've been thinking of making a canon like roof box that contains 6 Saiga 12s all connected to solonoids so I can fire the triggers from inside the VX.Throw some 20 round drums on each one, and have a nice lead thrower up top for any sort of situation that would require such a device.
I bet the shock wave from 6 rifles firing 12 guage slugs all at the same time might crack the windsheild though...but then again, it would certainly get those slow people outta the fast lane!
Bart