The power seems to be there, however, it's hard to tell now cuz the cats are clogged and the car is struggling to breath. If I decide to drive with the cats hollow, wouldn't that make the car sound loud?

My main cat, the one with the air pipe is a aftermarket cat...but the other two are used orig.....and your right about the redline, cuz if I rev the car up for a while you'll start to see smoke...maybe things will change after I replace the two cats and the 02 sensor...