Direct.
I don't know Stu.. I know of Dave Murchison.
I got the tune direct from the GDE website..
http://www.greendieselengineering.com/
They mail you the device to upload/down-load the tune.
Then you upload your OEM tune to the device, copy it to your computer and email your tune to them.
They then email you back you HOT or ECO tune.
Then you copy the file to the device from your email and load it to the Jeep.
The tune is locked to the VIN so it can only be used on your Jeep.
I talked with Keith at Green Diesel and he setup some settings the way I wanted them above the stock Hot or ECO tune.
I do still have my OEM muffler, but the lag is near zero and it light up all 4 285's.
I did try both tunes.
The ECO is night and day to the OEM.
The HOT is night and day to the ECO.
Last time I measured I got 9.52 km/Liter. That is running oversized tires 285, lifted, roof rack, arb bumper, and loaded down. The power band runs from 1800 rpm to 2200 rpm and in that band you get the best mileage. I found that out from talking with Keith at GDE.
I think the roof rack killed my mileage the most. I am going to take it off if I can figure out how to run my side and rear LED lights without it.