I installed the Green Diesel Engineering tune last night on my 2006 CDI with 78k miles. The process and instructions are fairly simple. You connect the device to your (Internet) PC and it automatically updates to it's latest version, and loads the dashboard on your PC. Then you connect the device to the ODB port on your car, and it reads and saves the current OEM ECU tune. Next hook the device back to the PC and download the tune file to the PC and email it to GDE support. Within a few hours I received an email back with the new tune file attached. Connect the device to the PC and upload the new file to it. Then connect to your car and load the new tune. During the load, my dashboard displayed a bunch of error messages and the radiator fan came on. This is all normal according to GDE. It stops once the load is done.

I took a 40 miles test drive. The cars display says I got 37mpg and averaged 38mph. As advertised, it appears to be a few mpg better than before. Throttle response seems more linear. I'd compare it to driving a car with a V8. It pulled strong before, but even stronger now. With the ESP off, it'll easily spin the rear tires from stop.

Is it worth the price? For me, yes. If I was living paycheck to paycheck, then no. The car ran really well stock. It's just a bit better now. But the device does all I was looking for. Better and more linear acceleration. Turn off the EGR valve. Better MPG. I can read and reset error codes. And if I want to switch from the GDE tune back to OEM for some reason, I can. And if a dealer or independent manages to somehow erase the GDE tune years from now, I don't need to contact GDE to reload it. It's all self-contained in the unit.

I'm happy.

Wanna race?