PA emission laws suck!
Im sorry to say that you're pretty much gonna end up failing it if you gut your cat. Unless you know the mechanic (or emissions guy, depending on if your mechanic takes the car out to be checked) they do a visual check (to see if everythings there), AND an electronic sniffer test. Now, sometimes you can get by the visual part because little things sometimes aren't noticed by the mechanic, and they don't know 100% about all cars (but they do know the majors), but the sniffers are a pain and will fail you even if your stock and in top shape sometimes (rarely tho'). Sorry dude, but best of luck anyhow!