Exhaust & Hi Flow Cat questions

[jjcivic92]

I have a 1992 Honda Civic, and I'm thinking about getting the old cat taken off and putting on a Jackson Racing Hi Flow cat. Then, I'm want to run 2" or 2.5" pipe from the exhaust manifold back. Here's the question .. Someone told me my cat was hooked into my header because I wanted to get it cut off, cleaned out, and put back on. But because of it being hooked to the header they couldn't do that. Is this even possible? That just dosen't sound right to me. Even so, could I still have it removed and have the hi flow installed with any problem? My Dad told me to chunk the resinator, is that a good or bad idea? What would happen to the overall performance of the car or would anything happen at all beside making my exhaust sound louder? Hope you guys/gals can help out. Thanks.