Mine are JBA Stainless Shorties. See
http://www.jbaheaders.com
I already had a Magna Flow exhaust system.
The truck sounds a little different in that it may be a little louder. Where I notice the difference is when I take off from a stop. Just seems to have more "balls". I also towed my boat last night and noticed a big change when I climbed a hill that leads in to my housing area.
We also slapped an Edelbrock Torque Arm on to replace that cheezy thin metal stock one. There was a difference there too.
I think I still need to mess with the Hypertech setting a little.