(I know you still have nightmares about that sound)

Fixed.

Now I need to figure out what the shudder/shake is at lower speeds. At first I thought it was the tires, but, now its pronounced when decelerating at lower speeds. U-joints all seem tight.

After the muffler was put on, I drove around running errands etc, just to put some miles on it. Put about 40 miles on it with no issues aside from that shake.