I have a 2001 z71 5.3 right now it has stock manifolds, stock cats then cut at the Y pipe and into true duals with 3" pipe all the way back to 2 flowmaster super 10's then dumped over the axle. I want to put on some headers, I was thinkin about getting the Pace Setter headers from ebay 1 3/4 to a 3" collector, I was gonna have that ran to the the dual 3" pipe, but I was wondering should I get high flow cats? or just straight pipe it? then get it tuned, what would make maximum power and sound the best?

 

No cats would be ideal for what your looking for. If you don't have to have them in your area, then get rid of them and tune out the rear 02's

 

That setup will be ridiculous loud and raspy and not to mention will drone like heck. I'd suggest adding cats or better mufflers. Not that those 10's are bad but they are straight through single chamber and will be loud!

 

I like it loud! haha but what would be the best for performance long tubes and cats or not?