Thanks for the replies everyone!

- The guy at freemuff told me that the rattle is from the inside of the cat, but I'll drop by nodalos to get a second opinion. I'd like to see if nodalos can open the cat and weld whatever is rattling in to in place, just to give me time to buy a new cat or look for a surplus one that will fit the car.

- Are there universal cats there that fit 2 inch diameter tubing? or maybe a free flowing cat for 2 inch piping? Just wondering, kasi I'm considering upgrading the exhaust system in the future for better performance.

- isn't the cat connected to the engine management system? Is there a sensor attached to it?