Check out some Duramax Diesel Forum sites like Diesel Place and Duramax Diesel. Both have a good EFIlive section. In those you can do a search for say ' best tuner ' and get some names of good tuners. As to what it cost it all varies on what you go with. Some can sell you a pretuned ECM and switch and you change out the ECM but most seem to be not doing this. Most are selling EFILive tuning with the EFILive Autocal hardware so you can flash your own ECM cheaper than buying EFILive full hardware option called the Flashscan V2. The Autocal is pretty much a handheld tuner setup with tunes you desire and have the ability to use it for data logging and code reader. The Autocal is a pretty much like the Flashscan V2 but limited in features that most users would never notice. Also if you go with the Autocal then you can only use tuning from the tuner that sold you the tuning. No other tuner can sell you tunes and allow you to flash them through the Autocal you have. Buying the Flashscan V2 from a tuner and this is not a limit. You can use anyone's tunes. But most go the Autocal route to save nearly 60% in the hardware cost to get going. I have only dealt with one tuner and that was DuramxTuner. You can google the name and get to his website and check out his offers. As a note he sells devices he calls the Jack and Spade. They are Autocal devices and just renames them for his business.

Brian