1970coupe

So im looking into exhaust systems for a GT. I want it extremely loud but also able topass inspection. I was thinking somewhere along the lines of headers, 3" piping, x pipe and 1 chamber flows. Or pypes "The Beast" Kit. Since the mustangs come with 4 cats i was thinking either taking out the rear cats or just taken them all off and puting in a o2 sensor simulator. Any one have any exhaust systems that sound mean but a way to just pass inspection. Ive never had inspection problems because i drive a 70 mustang coupe around so this is my first time getting into cats and that such crap.
Thanks!