The difference between banks headers and l&l headers (by themselves) are comparable.
Banks headers are stainless tubing.
L&L headers are made of schedule 10 pipe and nickel plated inside and out. Meaning they are thick, heavy duty, and won't rust.
I've had both setups and can say both are equally as awesome.

As far as hp numbers between the two, it's going to be very similar. Banks has tons of time and money invested into their setup, l&l in my opinion, just has a decent understanding of fitment and general header design.

I don't think you can go wrong with either setup. If you're a fabricator you could possibly save money using the l&l headers and get a diesel 4" catback, with some mandrel bent tubing and cats. Or find a deal on the banks complete setup and bolt it in place.

 

I live at the beach and rust is a ongoing issue so L&L sound like the ticket. thanks for the info. I already have 2 1/2" duel exhaust w/o cats and flowmaster mufflers. I'm going to put a crossover in since I didn't put one in to begin with. Any suggestions on a cam for the project? I'm putting in a Bully dog 6 way controller so I'm not sure if the cam would make a lot difference or not.

 

A bully dog what?
If it's a chip, and you haven't bought it yet, then don't. A chip for these truck don't do much at all other than timing and fool the ecu that it's colder than it really is. Getting tuning software like quarterhorse or tweecer will be money better spent.

As for a cam, something with 114 lobe separation is best, and 112 is ok. With tuning software 112 will be great.

Another benefit with getting tuning software is you will never be limited with what you can do. Bigger injectors or cam or boost or whatever.