I have never used the Stealth, but it seems to do the same thing that the Edge JWA I had before I deleted does and other modules do. Basically you disconnect the injector harness from the ECM and then re-connect the module's harness in between them. The module will "intercept" the fueling duration and timing commands that the ECM is sending to the injectors and alters them for more power. The plus side to this is that it does not remap the ECM so it doesn't leave a trace for the dealer to look for if something goes wrong, and the whole setup can be easily removed within 15 minutes.
There are a few down sides to this compared to a full remap tune. For one, it does not tune the trans to handle the added power like an EFI or EzLynk tune does. Trans tuning makes a huge difference in not only the longevity of your trans, but also in how the truck drives. I have Hardway and Anarchy EFI tunes and both are night and day difference in how they drive due to how they both tune the trans. I did a tune review of both earlier this year here(
LINK). If you are going to go with a module then I would recommend you add something like a
BD Line Pressure Booster. It does not alter shift strategies or TC lockup like a trans tune does, but it does add a little more line pressure then what is being commanded to allow the trans to better handle the added power.
Another thing that modules do not do is alter turbo actuation which plays a role in fuel mileage and other driving characteristics. It does not alter the throttle pedal sensitivity either which makes a huge difference in driving feel. You can get a BD throttle sensitivity booster or similar product to fix this though. Lastly, I did notice I was regening a lot more with the Edge JWA installed. It went from every 100 miles to aver 40 depending on the setting I had it on.
I added the Edge JWA at around 15k miles and got tired of it and did a full delete at 30k. I am now well passed my warranty period and never had it in for engine or drivetrain repairs aside from the water pump recall. My old pump was still working fine, but a free water pump is a free water pump.
Personally, I am not afraid of the Cummins having any warranty repairs due to my past experiences with multiple Cummins engines, but that is going to up to you. I can tell you that a good EFI Live or EZLynk tune will make the truck feel way batter than the Stealth or any other module will. There are tuners for those that want to keep their emissions intact as well.