Captain isn't quite pleased with some aspects of the tune. He has a post over on another forum ( not sure if against rules here to mention other forum names).
I have the tune and am very happy with it. I have 3.92 gears and didn't notice super acceleration improvement but I don't drag race the truck either, never really taking it above 2500 rpm.
Using my scangauge, I can say that the tune would pass an emissions obd scan.
I specifically like the egr fix this has done, lower required regens, the evic display changes, and of course the better gas mileage. On the highway I see nearly a 6 mpg increase over stock averaging overall to about 4.
Good luck with your decision
Well this forum has become that much more awesome to me then.You may post to other forums. It's sad that forum doesn't allow other forums to be posted. I'm here to help you guys, and all the info we can gather is always best for us!
Installed my GDE last week. Truck runs great, better acceleration, looks like a little better milage, no install problems, & exhaust break works well on steep grades without trailer.
I've been running the tune now for several months. For me it was not an earth shattering improvement in performance. The performance improvement is a bit more like your horse feeling his oats a bit more in the morning. Not the mind blowing the improvement some tunes give but at the possible expense 7-10%longevity.
This is a very conservative tune designed to not decrease the reliability of the truck. Soot/sludge buildup is less and my oil is definitely cleaner. I still didn't like the throttle response of the tuned truck and felt that while it was better than stock, it still left something to be desired. It felt pretty soft to me so I bought a throttle sensitivity booster. Much more satisfying to drive.
At the end of the day am I glad I bought it? My reserved answer is probably. I always have the feeling I'd like maybe another 30-40 hp/tq out of it to be really satisfied with the performance of the truck. The mileage is definitely improved. For me it has been about 7-10% overall. Even running my winter 10 ply tires (heavier than stock) and winter diesel, my mileage is better than it was with the truck stock and on summer fuel.
If I was pretty certain there would be not catastrophic engine failures like some have experience, I'd likely go with a bigger turbo setup that GDE has been testing. Supposedly it drops the 0-60 times to about 7 seconds flat and that would be quite satisfying as a daily driver. They didn't notice any decrease in fuel economy during normal driving. Apparently the stock turbo is the weak link for better performance.
So as it is, the GDE tune is a set it and forget it type of tune. Shouldn't hurt long term reliability from over stressing anything with excessive boost and fuel tuning. Quite likely it will help because of the reducing sludge and soot in the motor. You'll have to decide if it is worth the investment.