what you can do is remove the up stream o2 sensor from the rear exhaust manifold, this will make a damn good exhaust leak. if the the car has more power now the cats clogged. you need a o2 socket to remove it.
you can also put the car on ramps or jack stands, wait for it to cool off and bang on the cat and listen for it to rattle inside. if so its shot.
you can also drive it hard at night for a bit, then pull over to see if its glowing red. if so its clogged up.
if the cats bad the cheap way would be to have a shop just cut out the old one and weld in a new one. or buy a walker down pipe with cat.
being a 01 that year dont like the cat deleted.
