reffug said:aww fawk the cats. just my 02.
That is what I did with my 91. However, when I went to sell it I had to install them. I ended up with a dodge pickup application cat. It has two inlets and one outlet. Both are oversized compared to a Cruiser. It sits horizontal. The application was for a V8 so it should have plenty of flow. Tucked in nice. Didn't melt the carpet. No banging. I wouldn't recommend doing this if you have good cats as it set me back $240 for this new cat with install.
On the grinding. That might not be a good idea as the outer layer is a shield and it is filled with some fiberous material. If you open it up you may be adding moisture to your cat and allowing the rust demons to get inside easier. Also, if you do it you might want to wear a respirator. Who knows what that high temperature fiber stuff is made of? My guess is it is nasty.