How can i hollow out my Catalytic Convertor without affect the second oxygen sensor?
 

My cat is rattling like crazy. and i cant afford a new cat right now. so how can i hollow out my Cat without affecting the second oxygen sensor? it would be nice if it just flew out while driving because i have no muffler on it right now. i have 2 sensors, one before the cat and one after the cat. also i dont want it to negatively affect they way it runs or throw a code. its a 95 S10 CPI vortec "W" engine.... also what are test pipes?
let me know
thanks