I have ran my Smarty on the 60hp and 90 hp settings for over a year and the clutch is about gone. DD will go in this spring if she holds.

 

If I've collated the huge amount of data in all Smarty posts correctly, it appears the JR version may be the best fit for relatively stock trucks. I would guess that SW#2 (70hp) might be a sane solution for an 04.5 auto, and SW#3 would be okay for the 05 NV5600 - stock clutch. Close???

What might be the best solution for fuel economy when either truck is driven in a relatively conservative manner?

Once snow is on the ground, I'm not towing anymore and you can bet my truck will be back to stock SW. Even then it's mostly 4wd with studs.