Well today my original catalytic converter started knocking, so I droped the pipe to have a look and the aft ceramic block is just floping around in there, the cat is shot. So my question is do I replace it with a high flow aftermarket cat or test pipe? My car is a all orginal stock 87 GN with 43000 miles, I dont live in a county that does emissions testing so thats not a problem. I knew this day would come to start modding the car with aftermarket parts. So what would you do? any suggestions would be great!