I am not a tree hugger, but OP still better use the least expensive aftermarket cat instead of a straight pipe. You most likely never been in places where vehicles did not have catalytic converters.you could always remove the catalytic converter, break all of the honeycomb substrate (contents) out of it (use an old screwdriver, punch, etc), dump out the contents and re-install the now empty cat/pipe.
This just shows that he is mature enough.The OP did mention he was concerned about what would make "economic sense".
Not necessarily. Many people who are "flushed with cash" use a good "economic sense". That how they got "flushed with cash" in the first place.If the OP was "flushed with cash" he would just purchase a replacement catalytic converter.