Catalytic converters

This car has three catalytic converter. On it and I noticed one day when I hit the throttle hard a couple of times that pieces of the insides of the converter came out the tail pipe. So I ended up taking of the y pipe that has 2 small cats. On it and the one where the 2 pipe go into the other cat. Off, when I got them off I looked inside the single one and it was gutless, nothing in there, I put a scope in the other end where it bolts to the exhaust manifold and from what I could see it looked to be ok but I couldn't see everything. So do you think I should replace them or would it be fine the way it is? There is only one O2 sensor on the y-pipe before the cat. So no code was thrown and would it make the car run worse with the cats. Gone or what?