Not really the attitude we should have on a free website that is very against emissions law breaking..........
Now for the facts:
If you replace the cat with a straight pipe, it will sound like total crap, pop like hell, be iellegal, get you banned from trs if you brag, and stink up the cab (kill you in traffic, if you don't get it sealed properly soon)
But it's perfectly ok, to do that if it is extremely temporary, and you intend to get an aftermarket high-flow cat, it will also diagnose a clogged cat as the issue. If you replace it with piping (i don't know where your O2 sensors are located) it will run normal... but that doesn't mean it should be a permanent or good fix.
Frank