For those interested, I said I would follow-up once we got under my truck to look at the knocking and vibration I mentioned on previous posts.
We replaced the stock exhaust with a Borla and in the process found that the metal overlap on the right-side cat had about 1/10th of an inch of space between it and the frame of the truck. We also found the transmission mounts, as well as the motor mounts were badly sagging. So, essentially, under torque, the cats would move and vibrate against the frame. We installed the Borla, replaced the motor mounts, transmission mounts, plus notched the seam of the cat....and the knocking is gone.
Regarding the vibration.....for those that may remember, we thought the vibration around 20 mph was coming from the lift since I had just replaced the stock springs and shocks with HD springs and bilstein shocks. Well, we went though all of the checks that people on this site had given me....and we still had the vibration. The guy helping me called Rovers North and was discussing the vibration with them and they suggested we check the fan as they had heard of the clutch in the fan going bad and making the fan vibrate. Sure enough, we checked and my fan wobbles when you grab it so we ordered the clutch as recommended. Hopefully, that will take care of that problem. i didn't even know the fan had a clutch.
Lastly, in the "for what it's worth" file, the guy helping me has a Rover repair shop and has seen lots of trucks. He knew I was looking for more pick up but he was very skeptical when I ordered the RPI chip and essentially felt, as some of you did, that I was wasting my money. After driving my truck today he made a comment on how much quicker it was now and how much more fun to drive. he could definitely tell the difference with the chip. As I said before, it is probably not for everybody but it works in my truck.
Thanks to all that gave me advice regarding these annoying problems. This group has a wealth of experience and I, for one, really appreciate the help.