Honestly...
I would have rather had 3. 54s on my 3500 than 4. 10s. I used to pull my 17K lb 5th wheel w/ a 00 2500 w/ 3. 54s and all I had to do was downshift out of overdrive occasionally. It got better fuel economy running empty than my 3500 does. I run 70 - 80 mph in my 3500 and fuel economy suffers. I get 13 to 15 mpg.
I love the 3. 73s on my wife's rig.
Yeah, me too on the OBDII: Long-time coming.
Wiredawg