The Jards were an enigma to me. I got mine from N1 with relatively low miles and found them to be way too loud. I really liked the "graceful" contour of the headers though and the overall look. I in turn sold them to another forum member but afterward thought that perhaps I was too quick to do so. There must be a couple of generations of Jards. N1, Gorgerider and I encountered a guy in Oregon who had just bought a used Rocket with Jards installed and the sound was superb, deep and rumbling without the loud crack that mine had. Perhaps I should have tried a repack before selling them.
Of interest, you still use your O2 sensor. I have TORs with a hanso custom tune and the O2 sensor installed. I'm still on the fence about whether or not disable it.