I hated that mine sounded like a Prius and that you barely heard anything at WOT. When I had the Flowmaster Super 44 put on it a little grin gets on my face anytime I drive it, especially around town. Before the exhaust I drove it like grandpa and got good mileage out of the truck, since the exhaust I lost a couple MPGs around town and I drive it more like I used to drive lol.
I didn't get the JR kit, just the MIT tube and I don't think it helped with throttle response, but it sure cleans the engine bay up and makes it easier to get to everything.