I forgot to respond to your plugged cat question.

With the car idling, put your hand at the opening of the exhaust pipe. On a 4 cyl car, you should easily feel the individual bursts of exhaust. If you feel a steady blow, there is an obstruction in the exhaust.

Your car has a dual-wall header pipe from the exhaust manifold to the cat. The inside pipe will rust through first, and can end up causing an obstruction. You can hear that the engine sounds different when that inside pipe fails.