Check into Green Diesel Engineering. Not a tuner per say, but you can buy different tunes from them. Either send them your ECM or and they can sell you a flash tool so you can switch between the tunes they offer.
I have the ECO tune, and am happy with it. I think it improved my fuel mileage by 5-10%. Real advantage was that it reduces/eliminates the EGR input.
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2005 CRD "
Ol' Blue"
Red Ryder carbine-action, two hundred shot range model air rifle with a compass in the stock and this thing which tells time.
My build page- RL Komodo Rear and TJM Front Bumper, armored, lifted, JBA Steel D30, 4.10s and ARB air lockers.