I understand what a tuner does. Basically re-flashes your ECU with different information to make the truck run differently. What I am no longer understanding is the difference between the brands. They all talk to the ECU, and give it a new tune based on what company you buy the tune from. Is the interface the only difference? I'm not looking to buy a cheap knockoff system on Ebay or anything, so I don't want to compare those, but systems like EFI, MM3, Edge, Bullydog, etc... They can all put the same info in your truck, right? I like the idea of the monitor for seeing live data, and making changes when needed, but I don't want the monitor to be permanent. I like low profile. A manual selector switch is the only thing I want to have visible, and even that I will try to blend in to make inconspicuous. I am planning on upgrading my valve body, and would like a tuner in order to have transmission tuning for the new valve body. Removing or disabling emissions components does not need to be discussed in this thread. I've tried researching this on more dedicated diesel forums, but that is a whole other topic. Any help is appreciated, pretty sure I've started overthinking everything at this point.