I never liked gi joe's who cares how long youve been driving. You obviously dont know what your talking about, you say 4 stock cats will flow better then a free flowing pipe because it has more backpressure? What is backpressure? How does it work? You say an o/r hpipe helps up top, why? how do you figure? Why would cats restrict the car up top but not downlow, why would an o/r pi pe not be able to flow downlow but pick up at higher speeds? Do you blame it all on backpressure? Again what is backpressure? The term you should beusing is VELOCITY and cats does NOT give you more velocity. And I would not believe anything you are saying because like said before, its a mid pipe, stock, o/r or high flow cats you will FEEL NOTHING when your driving, and you have no numbers to prove your theory, so there are you. Your 20 or so years of driving has gotten you know where.