I just ordered and installed the JBD chip last week set at default settings.
Yes the engine feels a little stronger than before. The notice that came with it says "off road use only" so you may want to take it of for service and smog check if there is (do they smog diesels now?).
Not sure about the mileage yet, I only drove a quarter tank since I installed it. Do others see better, same or worse mileage ?
2011 BMW X5 35d 265HP 425TQ - Now with K&N & JBD Tuned !
2007 Audi Q7 3.6 280HP 266TQ
2000 Saleen Mustang 4.6 Supercharged 510HP 490TQ