Originally Posted by SPless
What?? I thought you knew stuff about cars and here you say the catalyst isn't a restriction? The catalyst adds backpressure for the engine, which is clearly a restriction.
There are bigger restrictions. You can only flow as much as the worst part of the system. Still, the exhaust isn't the biggest problem here. I don't always agree with JP7, but really, unless you want the sound, an exhaust on a stock truck doesn't do much.
There are things you can do on the intake side, which while not affecting peak hp numbers, can modify the off-idle "feel". Ok, you can flame me now JP.