Previously (May 2nd) I posted:

---Ok, the verdict is in....no increase in fuel economy was seen.
---One tip I recommend is to go ahead and have some replacement
---o-rings for the injectors in case any of them are dried out like mine
---were....one even broke when removed.  Beyond that, I still feel
---as though there was a slight increase in performance and wish I
---had done this mod years ago.

---2001 QC 2500 4x4

After several weeks and more miles, I can now say that yes indeed,
I have experienced an increase in mileage...a little over 10% in fact.
BEfore installing the kit and thermostat I was getting between 10.2
and 10.5 mpg in the city.  Now I am getting 11.5 minimum.  Could
this be because any residue was effecting proper operation of the exhaust
sensor?  And once that residue was burnt off and the ECU was getting
the proper info the ratio leaned out?  Beyond that, an obvious increase
in power and a cooler running temp are the only things I seem to have
noticed.

Translated into dollars, I expect to see a $400-500 savings per year
making the money and time spent to install seem trivial.  Again, I highly
recommend anyone that has not done this yet...to do it asap.